896 THE VOYAGE OF H.M.S. CHALLENGER. 



Habitat. — North-west Pacific, south of Japan. 



The carapace is about one-fourth the length of the entire animal, it is dorsally 

 smooth except for a large tooth that surmounts the gastric region in the median line, 

 and another that stands near the margin above the orbital angle. The rostrum is 

 slender, smooth on the lower margin, and armed with two unequal teeth on the upper 

 surface, of which the larger is the posterior, and situated about one- third from the base. 

 The outer orbital angle is rounded, and tipped with a small tooth that I take to be the 

 first antennal tooth, and the fronto-lateral angle is produced to a sharp point, whence 

 the lateral margin is smooth to the posterior margin of the carapace. 



The pleon is smooth ; the five anterior somites are subequal in length, the sixth is 

 longer and narrower, and the telson is longer than the sixth somite. 



The ophthalmopoda are pyriform and projected on a long and slender cylindrical stalk ; 

 they are 4 mm. long, or about one-third the length of the animal ; the ophthalmus is 

 rounded. In front, beneath the base of the rostrum, a large globular lobe projects 

 between the ophthalmopoda, on which exists a small ocellus. 



The first pair of antennae has the peduncle reaching nearly to the extremity of the 

 ophthalmopoda ; the first joint is long and armed at the outer side at the base with a 

 sharp-pointed stylocerite, and is but imperfectly defined by a small prominence from 

 the second joint ; the third joint is short and cylindrical, and supports two long slender 

 flagella, of which the upper is rather the more robust. 



The second pair of antennas is furnished with a scaphocerite that reaches beyond the 

 distal extremity of the peduncle of the first pair, it is rigid on the outer side and is 

 distally armed with a sharp tooth, and foliaceous on the inner side, the margin of which 

 is fringed with hairs. 



The oral appendages have not been examined. 



The first pair of gnathopoda have not been carefully examined, but appear to be 

 short, robust, and subpediform, with the distal joints reflexed. 



The second pair of gnathopoda is long, slender, and pediform ; it is six-jointed, and 

 terminates in a sharp-pointed dactylos, and carries a slender subequally long basecphysis 

 that has the margins parallel and the extremity blunt. 



The first pair of pereiopoda is scarcely as long as the second gnathopoda, it resembles 

 it in form and carries a similar basecphysis. The second pair resembles the first, but is 

 a little longer and perhaps also more slender. The third pair is much longer than the 

 second ; the meros is extremely long, the carpos shorter, and the propodos, which is 

 flattened and long, gradually increases and as gradually diminishes in diameter towards 

 the dactylos, which terminates in a straight sharp-pointed dactylos. The fourth pair 

 resembles the third, but is a little longer and terminates in a long, slender, styliform 

 dactylos, and, like the preceding, carries a long, narrow basecphysis. The fifth pair is 



