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



three long spine-like teeth, one in the median line of the carapace, and one on each side 

 of it ; they are directed upwards and a little backwards. 



The pereion has five somites developed, visible posteriorly to the carapace. 



The pleon has the five anterior somites subequal in length ; each is armed with a 

 central dorsal tooth on the posterior margin, and a large lateral spine-like tooth at the 

 postero-lateral angle. The sixth somite is longer than the two preceding ones together, 

 and is armed on each side at the postero-lateral angle with a long spine-like tooth. 



The telson is bilobed, each lobe is long, flat, and armed with a series of eight teeth 

 radiating from the margin. 



The ophthalmopoda are short, stout, and pyriform, but not much longer than broad, 

 and about one-fourth the length of the carapace. 



The first pair of antennae is one-branched and four-jointed ; the first joint is the 

 longest and is furnished with a ciliated hair on the one side and a small hair on the 

 other ; the second is about two-thirds the length of the first and similarly armed on 

 each side at the distal extremity ; the third is a little shorter, more slender than the 

 second, and is similarly armed, except that it has two ciliated hairs instead of one, and 

 the fourth joint is more slender than the preceding and is tipped with three ciliated 

 hairs. 



The second pair of antennas consists of a broad basal joint, which supports another 

 not quite so broad, that in turn supports two branches, the inner of which has three 

 joints, two of which are distally armed on the inner side with a projecting point bearing 

 two long ciliated hairs, and the terminal joint supports six. The branch on the outer 

 side becomes the future scaphocerite, and is flat, broad, and multiarticulate ; the outer 

 margin is unarmed except for one small hair near the middle, but the inner margin 

 including the distal extremity is furnished with nine or ten long ciliated hairs. 



The oral appendages are not easily detected, as the specimen being unique is mounted 

 for the microscope, and I hesitated to dismount it. 



Four pairs of pereiopoda are distinctly visible ; each consists of a strong basal joint 

 that supports two equal, flat and narrow plate-like appendages tipped with two small 

 hairs. 



The pleopoda are not yet visible even as buds, except the sixth pair, which is large 

 and well developed, consisting of a short basal joint armed with a long spine-like 

 tooth and bearing two long foliaceous rami, the external of which is tipped with five long 

 ciliated hairs and the inner with two. 



Length, 3 mm. (0"12 in.). 



Habitat-— Station 352, April 13, 1876; lat. 10° 55' N., long. 17° 46' W.; on the 

 surface of the Atlantic Ocean, off Sierra Leone ; surface temperature, 77°'7. 



I have said that the oral apparatus has not been well examined, but enough has been 



