CARCINOLOGICAL STUDIES. 123 



is a little shorter thau the two preceding segments taken 

 together, and a little more than once and a half as longr 

 as the penultimate segment. The terminal segment is slightly 

 longitudinally concave in the middle and presents two 

 pairs of spinules on the posterior half of the upper sur- 

 face near the lateral margins. The posterior margin of the 

 telson is armed with a short median , immobile spine in 

 the middle, on each side of which two mobile spines are 

 found ; of these spines the inner one is four times as long 

 as the outer, the latter being about of the same size as 

 the median spine. The lateral margins and the posterior 

 margin are ciliate. The uropoda are a little longer than 

 the terminal postabdominal segment, and their basal por- 

 tions are armed with two small spines above , the outer 

 of which is the larger one. 



The eye-peduneles , the half of which is occupied by the 

 cornea, are short and thick and as long as the rostrum. 

 The first joint of the peduncle of the inner antennae is a 

 little longer than the rostrum , and its upper surface is 

 somewhat enlarged and excavated ; the slender and acute 

 basal spine reaches the distal end of this joint. The two 

 following joints are short , subcylindrical and together still 

 a little shorter than the first; the penultimate joint is 

 slightly longer than the terminal one. The joints of the 

 antennular peduncle present no spine at their distal extre- 

 mity, but they are perhaps armed with a few microscopical 

 spinules. The two flagella have the same form as in the 

 genus Hetairus] the external one is stout and robust and about 

 as long as the peduncle, but the internal one is slender and 

 thin and twice as long. The peduncle of the external an- 

 tennae is slightly longer than the antennular peduncle ; 

 the basal joint presents two short spines on the anterior 

 margin of its outer side, the lower of which is a little 

 longer than the upper one. The antennal scale is a little longer 

 than the peduncle , and its external margin terminates in a 

 small spinule. The flagella are a little longer than the body. 



The external maxillipedes are elongate and project with 



Notes from tlie Leyden Museum, Vol. XLI. 



