INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 551 



Pencils Braslliensis Latreille. 



Edwards, Hist. nat. des Crust., tome ii, p. 414 ; Gibbes, loc. cit., p. 198 ; Stirnp- 

 son, Annals Lyceum Nat. Hist., New York, vol. x, p. 132. 



According to Stitnpson, this species has been found in the Croton 

 River at Sing Sing, New York, by Professor Baird. It will therefore be 

 very likely to occur in the rivers of Southern New England. It is com- 

 mon on the coast of the Southern States, aud extends to Brazil. 



SQUILLOIDEA. 



Squilla empusa Say. (pp. 369, 536.) 



Loc. cit., p. 250, 1818 ; Dekay, op. cit., p. 32, PI. 13, fig. 54 ; Gibbes, Proceedings 

 Amer. Assoc, 3d meeting, p. 199. 



Florida to Cape Cod. 



The young of this species is figured on Plate YIII, fig. 3G. 



MYSIDEA. 



Mysis stenolepis Smith, sp. nov. Plate III, fig. 12. (p. 370.) 



Male : Anterior margin of the carapax produced into a very short, 

 broad, and obtusely rounded rostrum, and each side at the inferior angle 

 into a prominent, acutely triangular tooth, between which and the base 

 of the ocular peduncle there is a broad and deeply rounded sinus. Pe- 

 duncle of the antennula about a third as long as the carapax along the 

 dorsal line ; the sexual appendage slender, tapering, nearly as long as 

 the peduncle ; inner flagelliim half as long as the outer. Antennal scale 

 rather longer than the carapax along the dorsal line, narrow, about ten. 

 times as long as broad, tapering to a slender and acute point, both edges 

 ciliated and nearly straight ; flagellum about as long as the rest of the 

 animal. Abdomen somewhat geniculated between the first and second 

 segments ; sixth segment about twice as long as the fifth. Appendages 

 of the fourth segment reaching nearly to the distal extremity of the 

 sixth segment ; inner ramus slender, slightly longer than the base j outer 

 ramus naked, composed of six segments ; the first, third, and fourth sub- 

 equal in length, and together equaling about three-fourths of the entire 

 length; the second, fifth, and sixth subequal; penultimate segment armed 

 with a stout spine on the outside at the distal extremity, and the last 

 segment terminated by a similar spine. Inner lamella of the appen- 

 dages of the sixth segment extending slightly beyond the telson, narrow 

 and tapering to an obtuse tip 5 outer lamella narrow, linear, about seven 

 times as long as broad, nearly a third longer than the inner, both edges 

 ciliated and nearly straight, and the tip narrow and somewhat truncated. 

 Telson considerably longer than the sixth segment, tapering slightly, 

 the sides nearly straight, and each armed with about twenty-four spines; 

 the extremity cleft by a deep sinus rounded at bottom, and its margins 

 convex posteriorly and armed with very numerous slender spines. 



Length of a male from tip of rostrum to extremity of telson, 23.2 mm j 

 length of oarapax along the dorsal line, 6.5 ; length of antennal scale, 

 6.7 ; length of telson, 3.8. Length of female, 30 mm . 



