ORDER DECAPODA — PALEMON. 29 
GENUS PALEMON. Fabricius. 
General form of the preceding. The internal antennz arise above the external ones, and ter- 
minate in three filaments. The first two pair of feet didactyle ; the second longer and 
more robust than the first ; the remaining feet monodactyle. 
PaLEMON VULGARIS. 
PLATE IX. FIG. 30. 
Palemon vulgaris. Say, Jour. Acad. Nat. Sciences, Vol. 1, p- 248. 
PB. id. Mitne-Epwarps, Hist. Nat. des Crustacés, Vol. 2, p. 396. 
ies squilla? GouLp, Invertebrata of Massachusetts, p. 332. 
Description. Rostrum acute, cultrate, dilated, and deepest under the middle, extending 
somewhat beyond the lamellar appendices of the external antenne, with eight or nine teeth 
on the upper edge, and three or four beneath with sete between them. Shield with two minute 
spines on the antero-lateral border at the bases of the external and internal antenne ; between 
the two spines, an obsolete furrow directed backwards. Peduncle of the lamellar appendix 
with a spine at the exterior tip. Two spines on the first joint of the interior antenne. The 
fingers of the first pair scarcely reaching middle of the palm of the second; its carpus with 
a spine, and longer than that of the second ; its fingers hirsute, minute, and nearly equalling 
the palm. The second pair with its fingers shorter than the palm ; carpus shorter than the fol- 
lowing joint; hands elongate ; finger somewhat deflexed ; thumb straight. Medial caudal 
plate with two movable prostrate spines placed on each side ; tip with three or four movable 
spines. External antenne two inches long. 
Color, light transparent sea-green mottled with brown; ocular peduncles spotted with 
yellow. 
Total length from the extremity of the rostrum, 1°5. 
This species is closely allied to the P. serratus, or Prawn of England, which is there con- 
sidered as a great delicacy. Our species is usually termed Shrimp, or Big Shrimp, to dis- 
tinguish it from the C. septemspinosus before described. It is distinguished from the English 
Prawn by the rostrum, which in this latter is bifid at the tip, and greatly exceeds the lamel- 
lar appendix of the external antennez ; it is also smooth near the front above, and the animal 
is from three to five inches in length. It is closely allied to P. squilla of Europe (La Cre- 
vette of the French), which is somewhat larger, with the rostrum straight, and not exceeding 
the lamellar appendix of the external antenne. The relative lengths of the fingers of the 
second pair in the two species disagree ; but without a direct comparison of specimens, it is 
impossible to determine in what particulars they may differ. 
