REPORT ON THE CRUSTACEA MACRURA. 607 



Length, 22 mm. (0-9 in.). 



Habitat— Station 233a, May 19, 1875 ; lat. 34° 38' N., long. 135° 1' E.; off Japan ; 

 depth, 50 fathoms ; bottom, sand. One specimen ; female, bearing ova. Dredged. 



The carapace is smooth, slightly carinated on the frontal region, anteriorly produced 

 to a slender rostrum that does not reach beyond the distal extremity of the peduncle of 

 the first pair of antennae ; it is armed with five teeth on the upper margin, three of which 

 stand on the frontal crest, the other two on the free portion of the rostrum, and with one 

 on the lower margin near the apex, which terminates in a single, sharp, elevated point. 



Pleon smooth, having the third and fourth somites gibbous, and the sixth somite 

 short and furnished with a small tooth-like spine. 



Ophthalmopoda long, pyriform ; ocellus close to the margin of the ophthalmus. 



First pair of antennas having the peduncle about the length of the rostrum, and the 

 flagella about equal in length to the peduncle. The inner and upper flagellum is very 

 much more robust than the outer, and the basal joint of the peduncle is furnished with 

 a sharp pointed stylocerite that reaches nearly to the extremity of the third joint. 



The second pair of antennae is furnished with a scaphocerite that is broad and 

 rounded at the extremity, armed on the outer margin with a short strong tooth, 

 and reaching beyond the distal extremity of the rostrum and nearly to that of the first 

 pair of antennae ; it also carries a flagellum that is slender and about equal to the length 

 of the animal. 



The second pair of gnathopoda is long, robust, and reaches beyond the distal extremity 

 of the rostrum. 



The first pair of pereiopoda is tolerably robust, and has the carpos long and 

 cylindrical, and the propodos still longer, and articulating near the middle of the 

 carpos. The second pair is long and slender, the propodos being equally so with the 

 carpos. The three posterior pairs of pereiopoda are not long but tolerably robust, 

 having the anterior distal extremity of the carpos projecting to a strong process or 

 blunt tooth over the base of the propodos ; the dactylos is bi-unguiculate, the concave 

 or posterior margin being furnished with several spines. 



The telson is tapering, subequal in length to the lateral plates of the rhipidura, and 

 tipped with two or three long spines. 



Observations. — This species corresponds closely with Stimpson's description of 

 Hippolyte gracilirostris, 1 which he found among stones at a depth of about 2 

 fathoms, in the Gulf of Hakodadi in North Japan, but it differs in several details. 

 Stimpson describes his species as " having the carapace smooth, with an anterior very 

 short carina ; the anterior margin being armed with only a pterygostomianal [fronto- 

 lateral] tooth. The rostrum being slender, straight, a little deflexed, short, not reaching 



1 Proc. Acad. Nat. Sci. Philad., 1860, p. 103. 



