REPORT ON THE CRUSTACEA MACRUEA. 799 



and behind and below this a hepatic tooth ; the frontal and lateral margins of the carapace 

 meeting at a slight! v obtuse angle, which, however, is not produced to a tooth. 



The pleon is dorsally rounded and laterally compressed, has the third somite longer 

 than the others and dorsally arcuate ; the sixth somite is nearly twice as long as the 

 preceding. 



The ophthalniopoda are short and pyriform, and the ophthalmus is round, with a 

 distinct ocellus on the margin. 



The first pair of antennae has the first joint of the peduncle longer than the two 

 succeeding joints, and is furnished with a stylocerite that is half the length of the joint, 

 which is armed on the outer distal angle with a sharp tooth. The second and third 

 joints are cylindrical and support two flagella, the inner of which is long and slender, 

 and the outer stout at the base and soon dividing into two branches, of which the 

 shorter is the chief and the more robust, and carries a series of membranous cilia ; the 

 secondary branch is as slender as the inner flagellum, and subequal to it, both being as 

 long as the carapace. 



The second pair of antennae is longer than the animal and supports a scaphocerite 

 that reaches beyond the extremity of the rostrum, and is armed on the outer margin 

 with a tooth that is behind the level of the anterior margin. 



The second pair of gnathopoda is short, slender, and pediform ; it carries a 

 basecphysis that reaches nearly to the penultimate articulation, and has the terminal 

 joint fringed and tipped with long, serrate hairs or spinules. 



The first pair of pereiopoda when extended reaches as far as the apex of the rostrum, 

 and is slender and chelate ; the carpos is as long as the meros and longer than the 

 propodos, inclusive of the pollex. The fingers are as long as the palm and impinge 

 closely together in their whole extent. The second pair is nearly twice as long as the 

 first ; the propodal articulation of the carpos, and the extremity of the dactylos, reach 

 as far again ; the meros is long and narrow, with the margins parallel ; the carpos is 

 narrow at the meral extremity and wide at the propodal ; the propodos is subcylindrical, 

 forms about half the length of the appendage, and is not much broader than the distal 

 extremity of the carpos ; the pollex is scarcely half the length of the palm, and the 

 dactylos is more curved than the pollex ; they meet together in their entire length. 

 The three succeeding pairs, so far as may be judged from the solitary member of the 

 posterior pair, are slender and not very long, the upper angle of the carpal extremity 

 overlapping the propodal articulation ; the propodos is long, straight, and cylindrical, 

 and the dactylos is long, slender, curved, and uniunguiculate. 



The pleopoda are biramose, long, narrow, and foliaceous. The rhipidura has the 

 lateral plates longer than the telson, and the outer extremity of the diaeresis jis armed 

 with a tooth and a spine. 



The telson is dorsally smooth, laterally compressed, and has the dorso-lateral angle 



