746 THE VOYAGE OF H.M.S. CHALLENGEE. 



The second pair has the scaphocerite a little longer than the rostrum, longitudinally 

 grooved, tapering, and abruptly terminating in a sharp point. 



Length, entire, ..... 



„ of carapace, .... 



,, of rostrum, .... 



„ of pleon, ..... 



„ of third somite of pleon, including tooth (2 - 5 mm.) 



„ of sixth somite of pleon, . 



„ of telson, ..... 



103 mm. (4 in.) 

 25 

 15 

 78 

 14-5 

 13 

 24 



Habitat— Station 106, August 25, 1873; lat. 1° 47' N., long. 24° 26' W.; Atlantic, 

 south-west of Sierra Leone; depth, 1850 fathoms; bottom, Globigerina ooze; bottom 

 temperature, 36°"6. One specimen; male. Trawled. 



Station 107, August 26, 1873 ; lat. 1° 22' N., long. 26° 36' W.; Atlantic, south-west 

 of Sierra Leone; depth, 1500 fathoms; bottom, Globigerina ooze ; bottom temperature, 

 37°*9. One specimen ; male. Trawled. 



Length 96 mm. 



This species bears some resemblance to Acanthephyra purpurea, but it may readily 

 be distinguished from it by the shortness of the rostrum and the less important dental 

 armature on the back of the pleon, and on closer inspection by the more abundant and 

 important spinules on the telson and the obtuse character of the scaphocerite. 



The ophthalmopod carries a small tubercle on the inner side, and the ocellus 

 is small and near the margin of the ophthalmus. Between the several pairs of 

 pereiopoda, as they succeed each other, may be observed the small articulating plate that 

 is very conspicuous in the genus Astacus and its fresh-water congeners, and also a strong 

 tubercle carrying a fasciculus of extremely long, flexible, shortly ciliated hairs that 

 penetrate between the branchial plumes. 



The scaphocerite (fig. 3c) is a little longer than the rostrum and has the terminal 

 tooth small and the inner squamous division slightly projecting beyond its point of 

 union with the tooth ; it is longitudinally grooved and ridged, and articulates between 

 two supporting teeth on the distal margin of the second joint. 



On the ventral surface, posterior to the fifth pair of pereiopoda, are two projecting, 

 large, and conspicuous tubercles placed closely together, that are connected with the 

 coxal joint ; they are apparently the calcified sheath of the penis, which I have observed 

 in another species. 



Observations. — Both specimens are larger than the Challenger specimens of Acanthe- 

 phyra purpurea and that of A. Milne-Edwards taken in the West Indies, but they are 

 of about the same size as a variety of the latter species taken at Station 318, in the 

 South Atlantic, off the south-eastern coast of South America. 



