REPORT ON THE CRUSTACEA MACRURA. 299 



armed with a posteriorly directed tooth, the extremity of which is depressed. Lateral 

 margins of the coxal plates unarmed. 



Telson subequal with the rami of the rhipidura. 



Length (male) 30 mm. (l"25 in.). 



Habitat.— Station 219, March 10, 1875; lat, 1° 54' S., long. 146° 39' 40" E., north 

 of New Guinea; depth, 150 fathoms ; bottom, coral mud. One specimen; male. 



This species differs from all those already described in the absence of deeply embossed 

 markings on the surface, and in the less pronounced condition of a series of vertical 

 ridges that mark the posterior portion of each somite of the pleon. 



The rostrum is slightly elevated, bidentate at the tip, smooth on the lower margin ; 

 the teeth on the upper margin are rather larger than in the other species. The 

 ophthalmus is large, reaching nearly to the extremity of the rostrum. The orbital 

 angle is produced to a point and the tooth on the hepatic region is rather small. The 

 teeth on the dorsal surface of the carapace are also small and not very elevated; the 

 anterior stands on the gastric region and the posterior immediately behind the cervical 

 fossa, whence a low but sharp carina extends to the posterior margin of the carapace. 



The first pair of antennae is short ; the prosartema is rudimentary ; the stylocerite 

 falls short of the extremity of the first joint of the peduncle ; the two succeeding joints 

 are short and terminate in a pair of small and slender flagella, that are not as long as the 

 last two joints. 



The mandible carries a synaphipod that is broad and flat. 



The first pair of gnathopoda is tolerably robust and hirsute, the second is long and 

 slender. The anterior three pairs of pereiopoda are slender ; the second is the longest, 

 the third very short, and the posterior two pairs are slender but not so long as the 

 third pair. The ventral tooth is long and styhform. Our specimen is smaller than 

 those of the other known species, but has all the features of an adult animal. It is a 

 male, and carries the protuberance on the ventral surface near and posterior to the coxa 

 of the fifth pair of pereiopoda. 



Hemipenseus, Spence Bate. 



Hemipenems, Sp. B., Ann. and Mag. Nat. Hist., ser. 5, vol viii p. 186, 1881. 



Animal slender, carapace without an hepatic tooth, rostrum short, horizontal, dentate. 

 Pleon compressed. Telson shorter than the outer rami of the rhipidura. 



Ophthalmopod single-jointed, having a small tubercle on the inner side. First pair 

 of antennae has the peduncle longer than the rostrum and terminates in two unequal 

 flagella, the shorter of which arises from near the base of the terminal joint, the longer 

 at the apex ; the first joint carries a rudimentary prosartema, and the stylocerite is want- 



