432 ME. L. EICHAEDSON & ME. J. F. WALKEE [Nov. I907 



Diagnosis. — Shell small, platyspheroidal, slightly broader than 

 long, with a prominent triplicated mesial fold. The ventral valve 

 is somewhat tumid in the region of the beak, but slopes slightly 

 towards the middle, where the deep mesial sulcus commences. 

 There are two ribs in the sulcus, and three prominent and three less 

 prominent ribs on each side. The beak is sharp, not very prominent, 

 and has acute beak-ridges. The dorsal valve is tumid near the 

 umbo, but becomes flat along the top of the fold, while it slopes 

 away on either side. Three ribs occur on the fold, and three 

 prominent and two less denned ribs on each side of it. 



Remarks. — Only one specimen of this distinctive shell has 

 come under my notice. 



Teeebeatula lenthayensis, sp. nov. (PI. XXIX, figs. 2 a & 2 b.) 



T.l. Lentliay, near Sherborne (Dorset). 

 H. Fullers' Earth. 



n. 



Colin. L. Richardson. . 



Diagnosis. — Shell elongato-spheroidal. Yentral valve regularly 

 convex, with a well-formed beak pierced by a conspicuous circular 

 foramen which almost touches the umbo of the dorsal valve. Dorsal 

 valve inflated and also regularly convex, without any indications of 

 flattening of the umbonal region. The anterior margin is but 

 slightly raised in mature specimens to form a wide fold. 



Remarks. — This fossil differs from Terebratula sphceroiddlis in 

 its regularly elongato-spheroidal form — not being so globular. In 

 the young of T. sphceroidalis the umbonal region of the dorsal 

 valve is flattened, and growth proceeds principally by additions to 

 the anterior margin, whereby the flattened area becomes more and 

 more turned towards the beak of the ventral valve, and parted 

 farther and farther by apparently-imbricating lamellae from the 

 anterior margin of the ventral valve. 



Teeebeatula DouLTiNGEJsrsis, sp. nov. (PL XXIX, figs. 1 a-1 c.) 



T.l. Farmcombe Quarry, near Doulting (Somerset). 

 H. Fullers' Earth (Knorri-Clajs). 



V. 



Colin. L. Richardson. 



Diagnosis. — Shell spheroidal in general appearance. Yentral 

 valve somewhat pyriform, inflated, incipiently monoplicate ; beak 

 large, gibbous ; foramen large and of Terebratula-decipiens aspect. 

 Dorsal valve also much inflated, especially in the region of the 

 umbo. Anterior margin with a well-marked fold. 



Remarks. — This species resembles a dwarfed form of Terebratula 

 globata, Sow., non auctt., but from typical examples is differentiated 

 by its more pyriform aspect, more inflated beak, and less conspicuous 

 anterior fold, which in the present species is monoplicate, while in 

 T. globata, Sow., it is incipiently biplicate. 



The present species has only been recorded from the Doulting- 

 Rridge and Farmcombe Quarries, near Doulting. 



