TETRAGONICEPS. 67 



apical setas ; inner branch of the second and third 

 pairs (fig. 9) not very much shorter than the outer 

 branch, that of the fourth pair (fig. 10) less than half 

 as long ; except a small, weak spine at the apex of 

 each joint of the outer branch, the feet are entirely 

 without spinous appendages ; each branch, however, 

 bears three apical setae, and the first joint of the inner 

 and the second of the outer branch have each one 

 seta. The fifth foot (fig. 11) is very large, consisting 

 of a single long, somewhat sternum-shaped joint, 

 broad at the base, then suddenly constricted and 

 tapering abruptly to the pointed apex ; three or four 

 marginal setae on the basal portion, and one towards 

 the apex. The caudal setae are short, the longest 

 being shorter than the abdomen. Length -^&th of an 

 inch ('9 mm.). 



Three specimens only of this interesting species 

 were found amongst dredged material from a depth of 

 twelve fathoms inside St. Agnes (Scilly Islands). Its 

 characters are so remarkable as to need no comment. 

 The generic name Tetragoniceps was applied first in 

 MS. to this species, but afterwards erroneously to 

 Laophonte thoracica * (" Tetragoniceps longiremis "). 

 So far as this latter species is concerned, the new 

 generic name necessarily lapses. 



* Brady and Robertson, ' Brit. Assoc. Report,' 1875, p. 196. 



