120 CARCINOLOGICAL STUDIES. 



I have a female specimen from Amboina before me, may 

 be distinguished by the following characters. The anterior 

 margin of the cephalothorax is entire, without even a 

 trace of a rostrum , the eyes are still much more promi- 

 nent laterally and the inferior margin of the meropodites 

 of the third pair of legs presents no tooth at its distal 

 end. I have shown , two years ago *), that the smaller hand 

 of A. latifrons presents a somewhat different structure in 

 young males and in the adult : in the latter the fingers 

 are quite as long as the palm , and the mobile finger is 

 much enlarged, in the young males, on the contrary, the 

 palm is distinctly longer than the fingers, and the mobile 

 finger is only very slightly enlarged. The male specimen 

 from Tahiti now presents quite the same differences when 

 we compare it with the adult individual, described by 

 Stimpson. 



A. pachychirus Stimpson inhabits the Loo Choo Islands 

 and Tahiti. 



Hetairocaris, nov. gen. 



A new genus of the Hippolytidae. 



The rostrum is short, slender, dentate above ; its lower 

 margin is entire and it arises from the anterior fifth 

 part of the cephalothorax. On each side of the rostrum a 

 supraorbital and one single antennal tooth; 

 the fronto-lateral angle of the cephalothorax is rounded. 

 The eye-peduncles are short and thick , the cornea occu- 

 pies about half the length of the eye-peduncles. The first 

 joint of the peduncle of the inner antennae is somewhat 

 concave above , and the basal spine reaches to the distal 

 margin of the joint. The two following joints are shorter, 

 subcyliudrical; the terminal joint supports two short flagella, 

 the external of which is the shorter and much more ro- 

 bust one. The basal joint of the antennal peduncle is armed 



1) Archiv f. Naturgeschichte , Jahrg. 53, 1888, p. 524. 



JS^otes from the Leyden JMixseuin , "Vol. XII. 



