REPORT ON THE CRUSTACEA MACRUEA. 725 



jection corresponding with the first antennal tooth ; the frontal margin then descends 

 and is lost in its continuation with the lateral margin of the carapace. 



The pleon is rather more than twice the length of the carapace ; the first two somites 

 are short and smooth, the third is longer, and armed with a sharp tooth that is horizontal, 

 and when the pleon is extended impinges against the dorsal surface of the next somite ; 

 the three succeeding somites are similarly armed, but the teeth are much smaller. The 

 sixth somite is laterally compressed, nearly twice the length of the fifth somite, and as 

 long as the telson, which is tapering and longitudinally curved. 



The ophthalmopod (fig. 3a) is about one-third the length of the carapace, and reaches 

 a little beyond the rostrum ; it is stout, being only twice as long as broad, and is 

 furnished with an ophthalmus of less diameter than the stalk, and supports a protuberant 

 ocellus. 



The first pair of antennae (fig. 3b) has a peduncle that reaches beyond the extremity of 

 the rostrum ; the first joint, which is subequal in length with the ophthalmopod, 'is broad 

 and slightly excavate, and furnished on the outer side with a sharp stylocerite that is 

 about half the length of the joint ; the second and third joints are broad and short, and 

 terminate in two flagella, the inner of which is short, slender, the articuli not being 

 clearly defined, and the outer flagellum is mul Particulate, and fringed with hairs on the 

 outer side and a series of membranous cilia corresponding with the number of articuli. 



The second pair of antennae is broken off at the extremity of the peduncle, the second 

 joint of which is furnished with a long, flat, foliaceous scaphocerite (fig. 3c"), the inner 

 margin of which is fringed with ciliated hairs, which are lost. Those present, being attached 

 to the new skin, are seen protruding through the orifices left by the previous hairs. 



The mandible and the other oral appendages have not been examined. 



The second pair of gnathopoda is long and slender ; it is probably six-jointed, but the 

 terminal part is broken off. The second joint is furnished with a basecphysis that is 

 about one-third its leno-th. 



O 



The first pair of pereiopoda is shorter than the second pair of gnathopoda, and carries 

 a long basecphysis, and terminates in a straight-pointed chela, the posterior margin 

 of the propodos being fringed with a series of closely planted ciliated hairs. 



The second pair of pereiopoda is considerably longer than the first, and Like it is 

 furnished with a long basecphysis, and terminates in a small chela that is not more 

 than one-fourth the length of the propodos ; the latter joint is not quite as long as, nor 

 of greater diameter than, the carpos ; the meros and ischium are fringed on the posterior 

 margin with a closely planted series of ciliated hairs. The third pair of pereiopoda 

 (fig. 3 to) is longer than the second, it carries a long basecphysis, and terminates in a 

 simple dactylos that is smooth on the posterior margin until near the base of the unguis, 

 where there is planted a fasciculus of long hairs, and this is also represented by similar 

 long hairs that fringe the distal extremity of the propodos, on the posterior margin of 



