510 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



The oral appendages are similar to tbose of Benthoccetes Bartletti, but 

 show some important differences. The ventral process of the crown 

 of the mandible, instead of being truncated at the anterior angle, is 

 prolonged into an acute angular process which closes by a similar pro- 

 cess of the opposite side. The palpus is verj' different in form; the 

 proximal segment is narrow, about three times as long as broad, readies 

 to about the tip of the crown, and expands very slightly distally; the 

 distal segment is only about half as long as the proximal and about as 

 wide at base, but the inner edge is obliquely truncated from just below 

 the middle so that the obtuse tip is narrow. The tirst maxillae differ only 

 very slightly and unessentially. Theendognathand epignath of the sec- 

 cud maxilla' differ very little, but the four lobes of the protognath are very 

 much more nearly alike, the distal lobe being only a very little broader 

 than the others, while the proximal is very much like the others, being 

 as long as the one next it and not narrowed toward the rounded tip. 

 The endognath of the maxilliped is a little shorter and the small ter- 

 minal segment either wanting or very obscure ; the exopod is shorter 

 and suddenly narrowed into a short and slender tlagelliform tip. The 

 exopod of the first gnathopod is very much smaller, being very slender 

 and considerably shorter than the endopod. The endopod of the second 

 gnathopod is more slender and armed with longer and stronger spines, 

 and the dactylus is very different, being nearly two-thirds as long as the 

 propodus, slender, subcylindrical, and strongly tapered distally, where 

 it is armed with several slender s])ines nearly as long as itself. 



The chelate peiseopods are similar to those of Benthoecetes Bartletti, 

 but considerably longer and more slender, the first pair reaching con- 

 siderably by the tips of the second gnathopods. The fourth and fifth 

 peraeopods are very long, exceedingly slender, and the proximal por- 

 tions nearly as in Benthcecetes Bartletti. The carpi in the fifth pair 

 are considerably longer than the meri; the propodi in the fourth are 

 much shorter than the carpi, and in the fifth not half as long as the 

 carpi ; the dactyli are slender, multiarticulate, flagelliform, and very 

 long, being in the fourth pair fully three times as long as the propodi. 

 The number and arrangement of the branchiai and epipods are the same 

 as in Benthoecetes Bartletti^ but there are small rudimentary exopods at 

 the bases of all the perteopods, as in Benthesicymus ? carinatiis. 



The pleon is very similar to that of Benthcecetes Bartletti except that 

 there is no spine on the fifth somite. The dorsum is evenly rounded on 

 the first four somites, but on the fifth and sixth there is a sharp median 

 carina which projects posteriorly in a very slight angle on each of these 

 somites. The epimera are all somewhat smaller than in Benthoecetes 

 Bartletti, and the posterior edges of the fourth and fifth project much 

 less and are broadly rounded. The sternum of the first somite is armed 

 with a laterally compressed mesial process somewhat as in that spe- 

 cies, but longer and obtuse. The pleopods have very long and slender 

 rami, as in Benthoecetes Bartletti, but the appendage (petasma) of the 



