REPORT ON THE CRUSTACEA MACRUEA. 301 



Hemipenseus spinidorsalis, Speuce Bate (PL XLIV. fig. 1). 



Hemipmams spinidorsalis, Sp. B., loc. cit,, p. 186. 



Rostrum longer than the ophthalmopoda, thin, armed with three teeth on the dorsal 

 surface ; crest not elevated ; inferior margin smooth and fringed with hairs. 



Pleon having the third somite dorsally carinated posteriorly, from the crest of which 

 a long, slender, posteriorly curved tooth projects, and a small dorsal ridge traverses the 

 posterior somite longitudinally in the median line and terminates in a minute tooth. 



Telson half the length of the outer ramus of the rhipidura. 



The ophthalmopoda are slender, furnished with a small tubercle on the inner margin, 

 and terminate in an orbicular, dark brown ophthalmus. 



The first pair of antennas has the first joint of the peduncle nearly as long as the 

 rostrum, and supports a strong stylocerite that is confluent with the margin, and reaches 

 nearly to the extremity of the joint ; the second joint is as long as the first, and sub- 

 cylindrical ; third joint short, carrying two flagella, one long and slender, and the other 

 short, flat and broad, the former articulating at the extremity, the latter at the 

 base. 



The second pair carries a scaphocerite that is twice as long as the peduncle of the first 

 pair, and is armed on the outer margin with a small, sharp, subapical tooth ; flagellum 

 twice as Ions; as the animal. 



The first three pairs of pereiopoda have the chelae long and slender, the pollex and 

 dactylus being twice the length of the palm ; the last two pairs are long, slender, feeble 

 and styliform. 



The pleopoda are very long, the first pair is single-branched, and the succeeding 

 pairs have a very slender second branch. The terminal pair is long, narrow, and 

 unequally branched ; the outer branch being much longer than the inner, terminating 

 in an ovate extremity, and furnished with a tooth on the outer margin. 



Habitat.— Station 133, October 11, 1873; lat. 35° 41' S., long. 20° 55' W.; near 

 Tristan da Cunha; depth, 1900 fathoms; bottom, Globigerina ooze; bottom temperature, 

 35°'4. Two damaged specimens. Trawled. 



Station 213, February 8, 1875 ; lat. 5° 47' N., long. 124° 1' E.; near the 

 Philippines; depth, 2050 fathoms; bottom, blue mud; bottom temperature, 38 - °8. 

 One specimen. Trawled. 



Length, male, 63 mm. (2 - 5 in.) ; female, 57 mm. (2"25 in.). 



This species, which is remarkable for a spine-like tooth on the third somite of the 

 pleon, has been taken in both the Pacific and Atlantic Oceans. The specimens from the 

 above localities correspond with each other very closely, even in apparently unimportant 

 details. Two of the teeth on the rostrum are situated near together in front of the 



