INVERTEBRATES. 407 



Anthrapal^emon gracilis, M. and W. 



PI. 32, fig. 4, 4 a, 46, 4c. 



Anthrapalxmon gracilis, Meek and Worthen, May, 1865. Proceed. Acad. Nat. Sci., 

 Philad., p. 50. 



It is with considerable doubt that we venture to refer this species to Mr. 

 Salter's genus, the only specimen we have seen being imperfect, and not in a 

 condition to show the more important characters. In form and general appear- 

 ance, however, as well as in such of its details as can be made out, it seems to 

 agree well with that genus. The specimen consists of the abdomen and 

 caudal appendages (in a crushed condition), and an impression in the 

 matrix of the under side of the carapace, the outer pair of antennae, and appa- 

 rently of the eyes. The carapace, as seen from above, presents nearly an 

 oblong form, excepting that the lateral margins are moderately convex in out- 

 line; the two extremities are truncated, and the breadth nearly or quite equal- 

 ing three-fourths the length. Its lateral margins, in front of the middle, are 

 each finely serrated by six small, sharp, projecting points, as in the type of the 

 genus, excepting that they are sharper and directed more obliquely forward. 

 At each antero-lateral angle there is also a considerably larger projecting point, 

 forming a short spine, exactly as in the type of the genus, excepting that it is 

 extended more nearly directly forward. The outer pair of antennae are moder- 

 ately stout, each peduncle showing three joints, diminishing rather gradually 

 in size, the first longer than wide and the other two apparently of nearly equal 

 length and breadth, and obliquely articulated. The flagellum is narrower at 

 its base than the last joint of the peduncle, and composed of very short seg- 

 ments, which are scarcely more than one-third as long as wide. The entire 

 length of the antennae can not be determined, as neither flagellum is entire in 

 the specimen examined; bift as the portion remaining tapers very gradually, 

 they were probably rather long. They are both, in the specimen examined, 

 deflected abruptly outwards, nearly at right angles to the longer diameter of the 

 carapace, which would seem, from the oblique articulation of the second and 

 third joints of the peduncles, to be their natural position. (Inner antennae 

 unknown.) 



Immediately between the bases of the two outer antennae, the specimen 

 shows what appear to be impressions of the two globose eyes, which with their 

 peduncles extend forward about two thirds -as far as the peduncles of the an- 

 tennae. These may possibly be the peduncles of the inner antennae; but they 

 look very much like globular eyes, on more slender peduncles. 



