40 ZOOLOGY OF THE VOYAGE OF THE SULPHUR. 



separated by a deep suture, profoundly cancellated ; many keeled, and furnished 

 on the lines of the striae of increase with numerous short bristles at regular inter- 

 vals. The aperture is rounded, and truncated at the base ; the canal so short as 

 scarcely to exist. Umbilicus small, and somewhat concealed by the inner lip, 

 which is slightly developed. 



167. Teichotropis inermis, Hinds, 1. c. p. 18, (Plate XI, fig. 13, 14.) Testa ovata, solidula ; 

 anfractibus quaternis rotundatis, multicostatis, longitudinaliter laevissime striatis ; costulis sub- 

 asqualibus, planulatis, inermibus ; apertura oblonga, canali brevi desinente; umbilico mediocri ; labio 

 interno producto. 



Inhab. Sitka, North-west America. Obtained in company with the pre- 

 ceding. 



In shape and outline this shell approaches T. borealis. It will be readily 

 distinguished from any hitherto known species by the absence of armature on the 

 epidermis, in which we lose sight in the instance before us of one of the characters 

 of the genus. The whorls are rounded and separated, as in the other species, by 

 a deep suture. The last whorl is remarkable for the strong ridges which it bears 

 at rather distant intervals, marking the termination or commencement of the 

 periodical stages of growth. In the method of formation of the canal there is a 

 close affinity in this shell to some Cancellarice , particularly in the angular-mouthed 

 species, and the affinity is extended to the character of the whorls and their con- 

 nexion by the suture. 



Family — Mitrace^e. 

 Mitra. Lamarck. 



168. Mitra Belcheri, Hinds, Ann. Nat. Hist. vol. xi. p. 255, (Plate XI, fig. 1, 2.) Testa, fusi- 

 formi, turrita, elongata, solida ; anfractibus laevigatis, insequaliter sulcatis vel exaratis, divisionibus 

 duabus superioribus majoribus ; epidermide nigra induta sed infra, lactea; columella quadriplicata ; 

 labio externo tenui. 



Inhab. Gulfs of Nicoya and Papagayo, Central America. Dredged from a 

 muddy floor in seventeen fathoms. 



This fine shell approaches the largest species of the genus, and is distin- 

 guished for its handsome symmetry. It is of an elongated fusiform shape, tur- 

 reted, the spire rather produced, and the last whorl occupying not more than half 

 of the entire length. The shell itself is milky white, but is everywhere covered 

 by a smooth black epidermis. The whorls are ploughed at unequal distances 

 with deep channels or sulci, of which the two superior divisions have the greatest 

 breadth, but the inferior of the two is the broadest. The columella is furnished 



