P. Modioli, (Montagui). Edinb. Ency.

P. Latreillii. Dict. des Sciences Nat.' xxviii.

Section 4. Orbiculata, have the carapace rhomboidal or ovoid, always solid; eye-pedicles short; claws of unequal length in the males and females, longest in the former; third articulation of the exterior jaw-feet always an elongated triangle.

CORYSTES, sub-genus.

C. cassivelaunus, Pennant; (personatus, Herbst.) shores, and sometimes thrown up during storms. and two females in our Museum. LEUCOSIA, (Ebalia, Leach), sub-genus.

Found on our sandy
We have two males

L. Pennantii. We have three specimens, obtained by Mr. Prideaux at Salcombe.

L. Cranchii. Two specimens in our collection, obtained in Plymouth Sound by Mr. Prideaux.

L. Bryerii. One specimen, obtained with the trawl at Plymouth, by Mr. Prideaux.

NOTE. Ad hoc genus pertinent species indigenæ Cancer tuberosus, Pennant, Brit. Zool.' iv., et Ĉan. tumefactus, Mont., 'Lin. Trans.' ix. (Leach, 'Linn. Trans.' xi.)

Section 5. Trigonia, have the carapace triangular, pointed anteriorly, and generally irregular and rough; claws, especially of the males, always large and elongated, the last articulation of the exterior jaw-feet always nearly square, or hexagonal: segments of the tail seven or less: many of them are called "sea-spiders."

PARTHENOPE, (Eurynome, Leach), sub-genus.

P. aspera. We have eight specimens of this crab, all young, sent by Mr. Prideaux from Bantham; who has also obtained them by the trawl in Plymouth Sound.

PISA, sub-genus.

P. Gibbsii. First found in Devon by Montagu, 'Linn. Trans.' vol. xi. Five specimens in our Museum were obtained at Plymouth and Bantham by Mr. Prideaux; they have also been found by Mr. Couch at Polperro, Cornwall.

P. Tetraodon, (Blastus, Leach). One specimen sent by Mr. Prideaux, who informs me that it was also found by Dr. Leach at Teignmouth. MAIA, sub-genus.

M. squinado, Thornback or King Crab; Corwich Crab, (Cornwall); Spider Crab of the Plymouth fishermen. We have several specimens; it is common here, and is occasionally eaten, though its forbidding aspect prevents its general use. It is always destroyed when caught, as the fishermen imagine it deters the edible crab from entering the crab-pots. HYAS, sub-genus.

H. araneus. Three specimens in our Museum from Plymouth Sound, obtained by the trawl.

H. coarctatus. Plymouth Sound and Salcombe; Leach, 'Linn. Trans.' xi., 239.

INACHUS, sub-genus.

I. Dorsettensis. Found in deep water at the mouths of rivers. We have three specimens from Salcombe; Mr. Prideaux.

I. dorhynchus. Discovered by Dr. Leach among some of the preceding species from Kingsbridge estuary. Mr. Couch says it is common in Cornwall.

I. leptorhynchus, (Leach, Mal. Brit.')
Mr. Prideaux, taken in Bigbury Bay.

ACHEUS, sub-genus.

We have two specimens from

A. Crunchii, (Leach, Mal. Brit.' 22). Found, though rarely, in Devon and Cornwall.

STENORHYNCHUS, (Macropodia, Leach), sub-genus.

S. tenuirostris. Plymouth Sound. We have four Devon specimens; it is also common in Cornwall, according to Mr. Couch.

Family 2. Decapoda macroura, or long-tailed Decapods.

Genus ASTACUS.

Section 1. Anomala, have two or four hind feet, always smaller than those which precede them; the under part of the tail never displays more than four pairs of appendices or false feet, the lateral fins at the end of the tail do not form, with the last segment, a fan-shaped extremity.

PAGURUS, sub-genus.

P. Streblonyx; (Cancer Bernhardus, Linn.); Hermit or Soldier Crab.Common on our coast. We have several small specimens corresponding to the description of Pag. araneiformis, but which Dr. Leach considers to be the young of the former. Mr. Prideaux tells me that he found two different species on this coast, one of which has been named after him by Dr. Leach.

P. Prideauxianus, Leach, 'Dict. des Sciences Nat.' tome xxviii.

Section 2. Locuste, have only four pairs of false feet, the posterior extremity of the fin forming the tail is always more membranous than the rest; all the feet are nearly alike, and pointed at the end; the thorax is almost square, without any lance-shaped prolongation.

SCYLLARUS, sub-genus.

S. tridentatus. In the collection of Mr. Comyns, of Dawlish, Edin. En. vii. 397; but I am doubtful if it is a Devonshire specimen. PALINURUS, sub-genus.

P. quadricornis, (Fab.); Thorny Lobster, or Sea Cray-Fish. cies is sold in our markets under the name of "Crawfish." common: we have one specimen in the Museum.

This speIt is very

Section 3. Astacini, are distinguished from the preceding by the form of the two anterior feet, which terminate by a didactylous hand; the extremity of the tail is fan-shaped; the thorax is narrow in front and the forehead more or less pointed. GALATHEA, sub-genus.

G. spinigera, or strigosa, (Leach); Plaited Lobster. Mr. C. Prideaux has

furnished us with two specimens from the estuary of Salcombe. It is about 6 inches long.

G. squamifera. Discovered by Montagu in South Devon, where it is not uncommon. We have four specimens, they are about 5 inches long. It is common in Cornwall, (Couch).

G. rugosa, or Bamfia. Very rare: Mr. Prideaux has only seen three specimens, which were obtained by trawling in Plymouth Sound. PORCELLANA, sub-genus.

P. platycheles. Found in Devon under stones, at low tides; Leach, Ed. Ency. vii. 398. We have four specimens. They are common also in Cornwall, says Mr. Couch.

P. hexapus, (Pisidia, Leach). Found on the roots of fuci after storms. We have one Devon specimen.

P. Leachii, Gray. I am not aware if this was found in Devonshire, although it is probable; it is common in Cornwall, (Couch).

MEGALOPA, sub-genus.

M. Montagui, (Cancer rhomboidalis, Mont.) Three lines long: found in Devonshire, Leach, Mal. Brit.'

M. armata, (Leach, 'Dict. des Sciences Nat.' tome xxviii). Found in Bigbury Bay, Prideaux.

GEBIA, sub-genus.

G. stellata, (Cancer Astacus stellatus, Mont.)

Obtained from Salcombe estuary, in holes in the sand made by solens &c. It is very rare; we have one specimen from that locality.

G. deltaüra. Found in similar situations as the last by Cranch and J. Sowerby Jun. Leach, ‘Linn. Trans.' vol. xi. 342.

CALLIANASSA, sub-genus.

C. subterranea, Found by Montagu in sand at Salcombe, “haud valdè infrequens," Leach, 'Linn. Trans.' xi. 343. We have two specimens from Mr. Prideaux.

AXIUS, sub-genus.

A. stirhynchus. Rare: specimens found at Sidmouth and Plymouth, Leach, 'Linn. Trans.' xi. 343. Mr. Couch has seen it in Cornwall, and thinks its rarity may only arise from its retired habits.

ASTACUS, sub-genus.

A. marinus, the Lobster. Common.

A. fluviatilis, (Lat.), the river Crawfish.

I am doubtful if this be com

mon in our rivers, as, on trying to procure specimens we are sure to have the Palinurus sent. We have, however, a good Devon specimen in our Museum, from Mr. Prideaux.

A. Norvegicus, (Nephrops, Leach). Rare: we have two excellent Devon specimens in our Museum.

Section 4. Carides, have the body arched and less solid than in the preceding; the front is always pointed, compressed, and toothed on its edges; antenne always advanced, la-、 teral ones very long, the exterior jaw-feet, being very long, resemble antennæ; one of the first pair of feet is often doubled on itself; the segments of the tail are dilated laterally; the exterior leaflet of the terminal fin always divided into two by a suture, the middle piece elongated and spinous above; the false feet, five pairs in number, are long and foliaceous. PENÆUS, sub-genus.

P. trisulcatus (Leach, 'Mal. Brit.' 42) of our coast is a local variety of the VOL. III.-No. 30. N. s.

2 G

Pen. sulcatus of Olivier according to Cuvier, ‘Règne Animal,' iv. 92. CRANGON, sub-species.

C. vulgaris, Shrimp. Common on our coast.

C. spinosus, (Pontophilus, Leach, Egeon loricatus, Risso). Obtained in Plymouth Sound by Mr. C. Prideaux. Mr. Couch says it is 1 inch long, with the carapace covered with spines in regular rows, and the chela singularly formed: he has only seen one specimen, which was taken from the stomach of a fish.

PROCESSA, Sub-genus.

P. canaliculata, (Nika, Leach). Found at Torcross by Montagu.
HIPPOLYTE, Sub-genus.

H. varians. Rocky shores of Devon, plentiful; Leach, ‘Mal. Brit.'
H. inermis. "Habitat cum præcedente; " Leach, 'Lin. Trans.' xi. 347.
Taken by dredging at Torcross; 'Linn. Trans.' ix.

H. Prideauxiana. Devon coast; Leach, 'Mal. Brit.'

H. Moorii, Plymouth. Named by Leach after a friend and cotemporary of his at Plymouth.

H. Cranchii. Found in the crab-pots here and in Cornwall.

PANDALUS, sub-genus.

P. annulicornis. Coast of Devon, common, particularly in summer, when they yield a greater supply than the true shrimp. Museum of the Plymouth Institution.

PALEMON, Sub-genus.

P. serratus, (Pal. Squilla of Latreille), Prawn. Devon coast; Leach, 'Linn. Trans.' xi. 343. They are not very common at Plymouth.— Museum of the Plymouth Institution.

P. Squilla. "Habitat cum præcedente in Danmoniâ australi vulgatè;" Leach, ubi supra.

P. varians. "Habitat in Danmoniâ;" Leach, ‘Linn. Trans.' xi. ATHANAS, sub-genus.

A. nitescens. Found in South Devon by Montagu; Leach, ‘Edin. Enc.' vii. 401.

Section 5. Schizopoda, have the feet void of pincers, slender, and in form of lashes, exclusively adapted for swimming; the ova are placed between them, and not under the tail; eyepedicles very short; the front is pointed or beaked, the shell is thin, and the tail ends in a fin, as usual.

MYSIS, sub-genus.

66

M. spinulosus, (Prannus flexuosus of Leach, Edin. Ency.' vii. 401; and Cancer multipes, Montagu, 'Linn. Trans.' ix.) Mr. Couch states that this has been named the " Opossum Shrimp," from carrying its ova and young under the thorax, but that he has reason to think it is the male only which does this, in a similar manner to the Syngnathi. It is common in Cornwall as well as here, and migrates regularly into fresh water.

M. (Cancer scorpionides of Montagu; Diastylis of Say. See 'Dict. des Sciences Nat.' tome xxviii. 337).

NEBALIA, sub-genus.

N. Herbstii.

Placed here by some, this species has been removed by Cuvier into Entomostraca, Order Branchiopoda. It is common both in Devon and Cornwall.

Order II.-Crustacea Stomapoda. These have their branchia exposed and adherent to five pairs of appendices, situated under the abdomen (the tail); their shell is divided into two parts, the anterior of which carries the eyes and intermediate antennæ, or forms the head, without bearing the jawfeet; these organs, as well as the four anterior feet often approximate the mouth in two converging lines; hence the name Stomapoda.

Family 1. Unipeltata, single-shelled Stomapods.

SQUILLA, sub-genus.

Genus SQUILLA.

S. Desmarestii. We have a good specimen in our Museum from Jersey. Mr. Couch has found it also at Polperro, which, being very near us, I have no doubt that future investigation will find it on our coast.

MALACOSTRACA with sessile, immoveable

eyes.

Order III.-Crustacea Amphipoda are the only Malacostraca of this division, whose mandibles are provided with a palpus, or whose sub-caudal appendages resemble false or fin feet, by their cilia, &c.; in the following orders these parts are lamine or scales; these cilia or hairs appear to constitute their branchia; many have vescicular pouches between their feet, the use of which is unknown; the antennæ, mostly four in number, are advanced, terminating in a point; body compressed and curved posteriorly; appendages of the tail resemble small articulated stylets; most of them swim and leap with facility, always on one side.

Genus GAMMARUS.

Section 1. Those with fourteen feet, all ending in a hook or point.

HYPERIA, sub-genus.

H.

Division 1. Uroptera.

(Cancer Gammarus monoculoïdes, Mont. ‘Linn. Trans.' xi.) PHROSINE, sub-genus.

P.

seum.

(Can. Gam. Galba. Mont. 'Linn. Trans.' xi.) Plymouth Mu

IONE, sub-genus.

Division 2. Gammarinæ.

I. thoracica, (Oniscus thoracicus, Mont. 'Linn. Trans.' ix.) found on the Callianassa subterranea, Edinb. Enc.' vii. 406.

ORCHESTIA, sub-genus.

O. littorea, (Can. Gam. littoreus, Mont. Linn. Trans.' ix.) Plymouth Museum.