136 Mr. E. A. Smith on Arctic Mollusca. 



Hah. OfF Cape Louis Napoleon, Grinnel Land, 79'' 38' N. 

 lat., in 25 fms. 



Only a single specimen of this grand new Trichotrojns was 

 obtained. It is very different from 

 any hitherto described, being remark- 

 able for its circular aperture, conical 

 spire, and extreme fragility. The 

 entire surface under the epidermis is 

 beautifully sculptured with oblique 

 raised lines or lirulse, and minutely 

 striated in a spiral direction between 

 them ; and the raised keels are also' 



similarly striated. The central keel of ^ - ■, ^ ^^ ^ 



,1 1 y 1 1 • 1 ••11 .1 1 ricnotroms tenuis. 



the last whorl is also visible on the ' 



upper ones, and is situated just above the suture. 



Dr. Gwyn Jeffreys, who has seen the specimen, considers 

 it a very abnormal form of T. hicarinata. Several other con- 

 chologists agree with me that it certainly is specifically dis- 

 tinct. The character of the epidermis is different, since it is 

 not produced into such very long ciliations as in the old species. 

 The keels are very slightly prominent ; the space between 

 them is convex, and not concave ; and, finally, the growth of 

 the shell appears to be quite regular, and does not display any 

 appearance of distortion, such as is usually observable in 

 abnormal growths of most species. 



TricJiotrojiis horealis^ Broderip and Sowerby, 



Zoological Joirrnal, iv. 1829, p. 375 ; Sowerby, Thesaurus Conch, iii. 



p. 321, pi. 285. f. 1-3 ; Fortes and Hanlev, Brit. Moll, pi. 101. 



f. 5-6; Jeffi-eys, Brit. Conch, vol. iy. pi. 4. f. 2, v. pi. 79. f. 6; Sow. 



Conch. Icon. xix. f. 1 a-c. 

 Trichotropis costellatus, Couthouv, Bost. Joum. Nat. Hist. toI. ii. 1839, 



pi. 3. f. 3 ; Sow. Thes. Conch, iii. pi. 285. f. 6 ; Conch. Icon, xix.f. 13. 

 T. acuminata, Jeffreys, Brown, Illust. Conch, ed. 2, pi. 57. f. 15. 

 T. atlantka (Beck),"M6Uer, Naturhist. Tidsskrift, 1842, p. 85. 

 Fustts uinhilicatus, Brown, Wemerian Memoirs, yiii. pi. 1. f. 2. 

 F. Laskeyi, MacgiUiyray. 

 Trichotropis inermis, Hinds, Voy. Sulphur, pi. xi. f. 13-14; Sowerby, 



Thesaui'us Conch, iii. pi. 285. f. 14 ; Conch. Icon. xix. f. 11. 



Hob. Discovery Bay, 5 fms. ; Dumb-bell Harbour (Feildefi). 



The specimens from the above localities agree precisely in 

 shape and sculpture with that form of this species which was 

 described by Hinds from shells found at Sitka, under the name 

 of T. inermis. It is said to differ from T. horealis in the epi- 

 dermis wanting the filamentous prolongations which usually 

 obtain in this genus. In the British Museum there are several 

 specimens of T. horealis which show various degrees in the 



