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



Pristiurus, Bonaparte. 

 Pristiuiiis melanostonms, Rafinesque. 



CoUett* records tlio rapturt' of this littoral species near Tromso, at a depth of 

 2.50 fathoms. 



Family N o t i d a n i d ^. 



Chlamydoselache, Garmau. 



Chlamydoselache anguinea (Pis. LXIV., LXY.). 



Chlamydoselachus angtdneus, Garman, Bull. Mus. Comp. Zocil., vol. xii. No. 1, 1885. 



I am indebted to M. S. Tegima and A. Sanders, Esq., for three well-preserved examples 

 of this shark, which hitherto was known from a single specimen only, a female without 

 intestines, and with a mutilated tail. Our specimens were caught in deep water in Yeddo 

 Bay, opposite Tokio. Two are males, of which the larger is 4 feet and 10 inches 

 long, the tail measuring 2 feet ; the third is a female, wliich had been eviscerated by 

 the fishermen, from whom it was bought. I am al)le to supplement Mr. Garman's account 

 by some remarks on the male claspers and other organs. 



The membranous margin of the ventral fin of the male is attached to the outer 

 and upper side of the clasper, leaving only the terminal third of the latter free, as is the 

 case in the Notidanidse generally, whilst in other sharks the fin and the clasper are separated 

 by a more or less deep notch (PI. LXIV. tig. C). 



The skeleton of the clasper is extremely simple (PI. LXIV. fig. D, D'). The 

 principal cartilaginous rod (a) is attached to the basale (h) of the pelvic limb by three 

 rudimentary and one larger intermediate cartilages (a'). The ventral side of its terminal 

 third is longitudinally concave, forming a half-canal which in its middle is bridged over 

 by a lobe-like expansion of the cartilage (I). A long calcified piece {t, t') with sharp 

 cutting edge is movably attached to each side of the end of the semicanal. These two 

 movable appendages can lie approached to each other so as to complete or close the canal. 



The structure is therefore very similar to that of Acanthias as figured by Gegenbaur.- 

 The cartilaginous ray (r) nearest to the clasper (or pterygopodium, Petri) is much elongate, 

 tapering, simple, occupying a position at about equal distance from the clasper and the 

 ray next above it. This latter (?•'), the penultimate of the series, is also elongate, and 

 consists of two pieces subequal in length, with a minute terminal piece, the rudimentary 

 condition of which leads me to suppose that it will not be found to be constant. The 

 third ray (/') is somewliat shorter than t])c second, consisting of two pieces, like the second, 

 l)ut without the rudimentary terminal. The following rays become successively shorter, 

 are composed of three pieces, and arranged closely side by side, as in the female fish 

 figured by Garman. 



' Nyt Mag.f. Naturvid, xviii., 1884, p. 117. ^ Jenaische Zeitschr., v., Tat", xvi. fig,-:. 15-17. 



