NATURAL SCIENCES OP PHILADELPHIA. 465 



"The pallets are of an angular ovate form, truncated posteriorly, where 

 also, on the external surface there is a small depressed area. The style of 

 insertion is sharp, and extends in the form of a ridge for some distance on both 

 sides after its juncture with the pallet. The tubes are very thin, strongly 

 concamerated posteriorly in an imbricated manner. This species differs from 

 T. megotara, Hanley, which it greatly resembles, in the smaller altitude 

 of the valves, the greater breadth of the auricle, which is also placed much 

 lower, and in its concamerated tubes. 



" Length of valves nearly one-half of an inch. 



" For many living specimens of this species, I am indebted to Mr. S. Tuft?, 

 of Lynn (Mass.), who obtained them from a pine buoy used to indicate the 

 position of the lobster pots of fishermen. Thus there can be no doubt of their 

 being indigenous. They commit yearly great ravages upon the shipping of 

 Lynn and Marblehead." Stimpson's description. 



T. divaricata, Deshayes. 



T. divaricata, Deshayes, MSS. Fischer, Journ. Conchyl., 2d ser. i. p. 137, 

 t. 7, f. 7, 8, 9. 

 T. Norvagica, var. divaricata, Jeffreys, Ann. & Mag. Nat. Hist. 3d ser. 

 vi. p. 121. 



Habitat. Sicily. 



Description. Shell globular, convex, heavy, full as wide as its length. An- 

 terior auricle very large and long, being two-thirds the length of the fang ; 

 its anterior margin thick, appearing almost ribbed, somewhat concave but 

 nearly straight, inclining outwards ; basal margin very convex, joining the 

 fang by an acute angle. The fang is but slightly raised above the anterior area 

 and is itself somewhat lower, or nearly on a level with the margin of the pos- 

 terior auricle ; the whole dorsal edge of the shell is slightly convex. Lateral 

 margins of the fang inclining obliquely, with the ventral termination truncate. 

 Posterior auricle very small, (almost none,) much longer than wide, but its 

 basal margin does not extend nearly so far down as that of the anterior area. 

 The latter is covered with concentric strise, which, at its junction with the 

 body, are recurved obliquely downwards and posteriorward. The space be- 

 tween the centre and posterior lateral margin of the fang, appears to be occu- 

 pied by the same double, narrow, closely striated radiating area, that is found 

 on the anterior side in T. megotara, &c. Posterior auricle somewhat 

 striated. Internal dorsal margin very wide and massive. Apophysis wide, 

 recurved backwards in front. 



Pallets truncate, resembling those of T. Norvagica, their blades very 

 short. 



Mr. Jeffreys considers this a variety of T. Norvagica, but, if Fischer's figures 

 can be depended on, it is certainly very distinct from that species. It may be 

 proper to add, that my description is made up from that of Fischer, and his 

 illustrations. 



T. malleolus, Turton. 



T. malleolus, Turton, Conch. Dithyra, p. 255, t. 2. f. 19. Adams, Genera, 

 ii. p. 333. Brown, Conch. Gt. Brit. p. 116, t. 50, f. 16. Fleming, 

 Brit. Anim. p. 454. Gray, Phil. Mag. 1827, p. 410. Gray, Ann. & 

 Mag. Nat. Hist. 2 ser. viii.'p. 386. Hanley, Desc. Cat. p. 4, t. 11. f. 23. 

 Hanley, Brit. Moll. i. p. 84, t. 1, f. 12-14. Jeffreys, Ann. & Mag. Nat. 

 Hist. 3d ser. vi. p. 123. Sowerby, 111. Brit. Shells, t. 1, f. 5. Thomp- 

 son, Fauna of Ireland, Ann. & Mag. Nat. Hist. xx. p. 174. Thorpe, 

 Brit. Mar. Conch, p. 28. 

 Hab. England, Ireland, (introduced.) Native habitat Sumatra. 

 Description. Valve, with the body very convex, narrow, much longer than 



1862.] 



