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



Station 285, October 14, 1875; lat. 32° 36' S., long. 137° 43' W.; South Pacific 

 Ocean ; depth, 2375 fathoms ; bottom, red clay ; bottom temperature, 35°. One 

 specimen ; male. Trawled. 



This species is remarkable for the long and slender spine-like tooth on the posterior 

 margin of the third somite of the pleon, the length of which is in marked contrast with 

 that of all the other teeth, which are peculiar for their smallness. 



The ophthalmus (fig. 4a) is of smaller diameter than the ophthalniopod, and is situated 

 on the outer surface of the extremity. 



The first pair of antennae has the sensory cilia long and thickly packed together, and 

 attached to the under surface of the base of the larger flaeelluni. The tooth at the outer 

 margin of the distal extremity of the scaphocerite is small and unimportant. 



The chelae of the two anterior pairs of pereiopoda are small ; the dactylos of the 

 third pair is rather short, slightly curved, and serrate on the inner surface, and that of the 

 posterior pair is short and almost obsolete. 



Observations. — There are only two specimens in the collection ; the more perfect is 

 a male, and has the anterior branch of the first pair of pleopoda small, foliaceous, sub- 

 membranous, and furnished with a small stylamblys without cincinnuli. 



Both specimens were taken at a great depth and about 7000 mdes apart. 



Acanthephyra media, n. sp. (PI. CXXIV. fig. 5). 



Carapace dorsally flat and smooth to the frontal region, where it is laterally com- 

 pressed and horizontally produced to a rostrum that is subequal in length with the 

 carapace, the upper surface is armed with small teeth, which are numerous and closely 

 packed at the base and widely separated towards the apex, and on the under margin with 

 one (or two) at the base. 



Pleon carinated, third and three succeeding somites being armed with a small 

 tooth. 



Telson long, tapering, and fringed on the distal margins with five or six small 

 spinules. 



Ophthalmopoda short and pyriform. 



First pair of antennas having the peduncle less than half the length of the rostrum. 



Second pair of antennas having a scaphocerite that is shorter than the rostrum ; the 

 flagellum is broken off at the length of the rostrum. 



The rest of the appendages are imperfect, excepting the second pair of gnathopoda, 

 which is slender, and the sixth pair of pleopoda, which has the external branch subequal 

 in length with the telson. 



