CHAP. IV.] ST. THOMAS TO BERMUDAS. 247 
chele of the first pair of legs are strangely developed, particu- 
larly the right chela, which is double the length of the left, and, 
with its formidable ranges of long spines along the inner border 
of each claw, reproduces on a small scale the jaws of the Gan- 
getic gavial. The last segment of the pereion is not covered 
by the carapace, but is in movable connection with it. The first 
segment of the abdomen is very small, and the segments grad- 
ually increase up to the fourth, which the fifth and sixth equal 
in size. The abdominal segments are flattened from above 
downward. The telson is quadrate, and combines with the two 
pairs of caudal appendages, which are widely expanded laterally, 
to form the caudal fin. The dorsal surfaces of the second, third, 
and fourth abdominal segments, and the margins of the tail, are 
thickly covered with woolly hair. The individual being a male, 
the first pair of swimmerets consist of long, slender appendages, 
and the four succeeding pairs have one strong, round, basal 
joint, to which are attached two palpi fringed with hair. As 
has been already mentioned, there is some resemblance between 
this form and Calianassa ; but in that genus the lamellar ap- 
pendage to the outer antenna is absent: there are four pairs of 
limbs with chelz instead of three, and the carapace is soft. To 
the genus Astacus, therefore, with which it has all characters 
in common except the great development of the right chela and 
the total absence of eyes—neither a character of generic value 
—the present species must be referred. 
A. zaleucus, v. W.-S. 
Rostrum spiny, elongated. Lamellar appendage of the outer 
antenna reaching to the middle of the second joint of the fu- 
niculus. Chelze on three pairs of ambulatory feet, those on the 
first pair strongly but unequally developed. Cephalo-thorax 
very much compressed laterally. Eye-stalks and eyes entirely 
wanting. 
On Sunday, the 16th of March, we anchored in the Gregaria 
channel at the entrance of the harbor of Charlotte Amalia. 
