264 PKOCKKDINGS OF THE MALACOLOCIICAL SOCIETY. 



ON SOME NEW SPECIES OF BRITISH MOLLUSCA, FROM THE 

 "TRITON" EXPEDITION, WITH A LIST OF OTHER SPECIES 

 NEW TO THE FAROE CHANNEL. 



liy Henky K. Jordax, F.G.S., etc. 



Read April 19th, 1895. 



PLATE XVI. 



The Mollusca obtained by the " Triton" Expedition in 1882 from the 

 "Faroe Channel" were described in the Proc. Zool. Soc. for 1883, 

 part iii. 



A small quantity of material from the same locality lately came into 

 the writer's hands, and has furnished several species which appear to 

 be new and undescribed, as well as some known species not recorded 

 in Dr. Jeffrey's paper. 



It maybe well to state that the localities in the "Warm area" from 

 which these new species were obtained are about 80 or 90 miles north 

 of the Butt of Lewis, being considerably nearer to our islands tlian 

 to the Faroe Isles. The depths varied from 433 to 570 fms., and tlie 

 bottom temperatures rangecl from 43-5° to 46-5° Fahr. The "Cold 

 area" is contiguous to the "Warm area," but separated by the 

 " Wyville -Thomson Ridge," over which the depth of the water is 

 from 200 to 300 fms., and the bottom temperatures range from 29-5° 

 to 32° F. at depths varying from 327 to 640 fms. 



Dentalium ^nigmaticum, n.sp. PI. XVI, Fig. 1. 



Shell sub cylindrical, very slender, thin, slightly curved, lustreless, 

 and opaque. Sculpture, 26-28 longitudinal ribs, which are thin, 

 almost sharp, and traverse the entire length of the shell. No 

 longitudinal microscopical striae are visible between these ribs, merely 

 the usual transverse lines of groAvth. Colour, creamy white. Margin 

 at the anterior end jagged, as is usual in other species of tliis genus. 



No notch or slit is visible at the posterior end, which, however, 

 appears when examined by a strong lens to be slightlv broken. 

 Long. 25, diam. 2 mm. (L. 1-0, B. 0-08).' 



One specimen only was obtained from the " Cold area." Station 

 No. 8 : 640 fms. ; bottom temperature 30°. This is a puzzling 

 species, and scarcely two opinions of the authorities, botli British 

 and Continental, whom I have consulted, are quite in accord. 



From D. ar/ile this species may be distinguished by the persistent 

 ribs which traverse the entire length of the shell, and by its some- 

 what more slender form. Herr Herman Friele informs mc that 



' For the courenience of those working;' with Dr. Jeffreys' Brit. Conch., the 

 equivalent dimensions in inches and decimals of an inch are added in each case. 



