112 Prof. W. B. Benham—A Giant Fossil Cirrijjede. 



justified in transferring it to tbis genus till a greater number of 

 valves have been studied, especially in consideration of the difficulties, 

 pointed out by Darwin, of distinguishing the two genera from the 

 valves only ; and it must be borne in mind that the criteria put 

 forward by him are not applicable to the living forms, for he 

 expressly limited them to fossil representatives. 



The only character referred to by Sir J. Hector is the great size 

 of the fossil ; and certainly this is, as it happens, a sufficient diagnosis 

 of the species. The largest capitulum known amongst living species 

 of Scalpelhim is that of Sc. Darioinii, Hoek, which attains a length of 

 46 mm. (nearly 2 inches) ; and only a few other species approach this 

 size, viz., Sc. eximium, Hoek, 43 mm. ; Sc. gigas, Hoek, 40 mm. ; 

 and an undescribed species in my possession from the coast of this 

 island is of the same length as the last. Amongst fossil forms, 

 the largest capitulum recorded by Darwin is 1^ inches (about 37 mm.) 

 in length, and only two entire capitula reached this size, viz., 

 Sc. magnum and Sc. maximum. 



Turning to Follicipes, all the known species are of small size; 

 existing forms are less than 1 inch (25 ram.), and the only entire 

 capitulum described by Darwin was | inch (say 13 mm.) in length. 



It will be seen, then, that the capitulum of the species of which 

 certain valves are described in the present article was of extra- 

 ordinary size ; it must have attained the enormous length of nearly 

 a foot (300mm.), and possibly more; for the tergum would, by 

 analogy with other elongated species, project considerably beyond 

 the scutum, while the inferior valves would still further add to the 

 length. 



The material at my disposal includes four recognizably identifiable 

 valves, with some fragments insufficiently complete to describe, 

 though one amongst the latter is, I believe, a portion of one of the 

 lower series of the capitulum, probably the ' carinal latus.' 



The four recognizable valves are — 

 (a) The carina, 

 (h) The scutum of the left side. 



(c) The rostrum (?). 



(d) One of the lower whorl (? the ' upper latus '). 



But there is no evidence to show that these plates belong to one 

 and the same individual. 



(a) The Carina. (PI. X, Figs. 3-7.) 



This valve is represented by one almost complete specimen and 

 another less complete, and some broken fragments. 



The more complete valve consists of a median, transversely ridged 

 roof-plate, a ' tectum ' (of Darwin), with a pair of inflexed ' parietes ' 

 forming a flange on either side. 



The tectum is long, narrow, nearly flat at the basal extremity, 

 but much arched from side to side distally. It is gently curved 

 in the longitudinal direction, but there is no evidence to show that 

 it was angularly bent upon itself. The basal extremity is uninjured ; 

 the inner surface slopes gradually to meet the outer surface, so that 



