188 Mr. R. Templeton's Descrijjtiojis of 



the 3rd nearly as long as both taken together, spindle-shaped, and 

 supporting the extreme joints, which are reniform, closing upwards or 

 forwards on each other as the finger does into the palm of the hand, 

 the apical joint having two long hairs arising from its tip. The 

 anterior leg (?) with two elongate joints projecting beyond the facial 

 plates, the tip surmounted by two hairs. Second leg with a large 

 dilated tarsus, and a strong claw directed forwards, closing on the 

 tarsus during each sweep of the leg with a snapping motion, rapid 

 and very peculiar. The third pair of legs resembles in every re- 

 spect the first pair, excepting that it is more profusely furnished 

 with hairs at the tip. From the three succeeding abdominal an- 

 nuli proceed inferiorly 4-articulated appendages or fin- legs, elongate 

 and hairy, especially at the tips ; and between these and those of the 

 opposite side curves forwards the tail, which terminates in a thin an- 

 giQated hyaline process. 



This singular little animal swims with great rapidity, the antennar 

 being widely separated, and their apical joints almost in perpetual 

 motion, seizing apparently on objects so minute as to escajDe my no- 

 tice. When at rest the tail and posterior legs were folded in, and 

 the antenn?e downwards, so that the animal resembled a ball, a pe- 

 culiarity noted by Risso in his genus Typhis ; there were here how- 

 ever no thoracic plates beneatli which they could be concealed. The 

 snapping spring-like motion, M^ith Avhich it moved the claw of the 

 second pair of legs struck me as very peculiar, and as indicative of 

 a degree of vivacity which is rather rare among the smaller CrustaceOy 

 as they usually seize upon objects with an appearance of delibera- 

 tion and dread, the result most probably of dear-bought experience^ 



Fig. 4. a, Natui-al size. 



b, The animal as it appears when swimming. 



c, A very magnified view. 



d, The tail. 



e, e\ The last joints of the antennae, exhibiting the apical stretcfied out 



and fokled in upon the other. 

 /, The claw of the second pair of legs, with the tarsus on which it plays, 



Cerapus {Say) abditus, Plate XX. fig. 5, 

 Brownish, antennee and legs paler. Body elongate, composed of 

 about 14 rings, including the head and tail, the latter having about 

 3 joints. The head is large, subtriangular, most dilated anteriorly, 

 a minute rostrum projecting forwards between the superior antennae. 

 The eyes are nearly sessile and smooth. The front is almost verti- 

 cal and gives origin to four nearly equal antennae ; the superior ta- 

 pering, about |rds as long as the body, has three joints of nearly 



