36S MOLLUSCA. ACEPHALA. Lingula. 



PEDUNCULATA. 



Gen. LINGULA. — Valves equal, oval, flat, without teeth or 

 elastic ligament ; peduncle cylindrical and cartilaginous ; 

 margin of the cloak fringed with fine hairs. 



1. L. mytilloides.— Ovate, anterior end slightly truncated ; beak indistinct. 

 —Mussel, Ure, Ruth. 310. tab. xvi. 6 — Sower." Min. Conch, t. xix. f. 1, 2 — 

 Carboniferous Limestone Casts of a shell imbedded in shale in the coal for- 

 mation, figured by Ure, Hist. Ruth, 310. t. xvi. f. 5., probably belong to a 

 species of this genus. They seem to have a mesial ridge, with diverging 

 striae. 



2. L. tenuis. — Elongated, lanceolate, anterior end truncated. — Sower. Min. 

 Conch, t. xix. f. 3. — London Clay. 



3. L. ovalis Depressed, oblong-oval, anterior edge circular, beak very 



short.— Sower. Min. Conch, t. xix. f. 4 London Clay ? 



Gen. XCI. TEREBRATULA.— Inequivalve, apex of the 

 largest valve perforated or emarginated for the passage of 

 the circular ligament ; hinge consisting of a projection on 

 each side the apex, and two elongated processes for sup- 

 porting the arms on the smaller valve, projecting into the 

 cavity. 



366. — T. cranium. — Shell ventricose, semitransparent, front 



margin slightly truncated ; surface finely shaggreened, and 



slightly wrinkled concentrically. 



Mull. Prod. 249. No. 300G Zool. Dan. t. xciv. f. 1 T. vitrea, Flem. 



Edin. Encyc. vol. vii. DC. t. 200. f. 2. — T, cranium, Mont. Linn. 

 Trans, xi. 188. t. xiii. f. 2 — Occasionally brought from deep water by 

 the cod-fishing-lines, Zetland. 



Length an inch and T l 5 th, breadth , 2 „ths less; brownish- white; the shag- 

 greening is remarkably delicate, and seen only by the help of a lens ; the la- 

 teral teeth of the large valves are bifid ; those in the small valve give origin 

 to the two projecting processes, which have a small tooth near their base, 

 and project horizontally, upwards of three-fourths across the shell ; the con- 

 centric wrinkles of growth occur irregularly ; peduncle simple — To this pro- 

 bably belongs the Anomia Tercbratula of Turton's Conchological Dictionary, 

 p. 5.", where a reference is made to Da Costa's Elements, 292. t. vi. f. 3., and 

 where it is stated that a single specimen was dredged up alive in Dublin Bay, 

 and placed in the Museum of the Dublin Society. 



367. T. psittacea. — Shell oval, with regular fine longitudinal 



striae ; the beak much produced and curved ; the margin waved. 



List. Conch, t. ccii. f. 46. Turl. Conch. Diet. 5. t. xi. f. 42. Biv. Brit. 

 236. — Cast ashore, after a severe gale, at Teignmouth, where Dr Tur- 

 ton has since seen several fragments. 



