OF CONCHOLOGY. 



151 



Fig. 27. 

 Fig. 27. Thecidlum medilerrdneum, hirmal valve with the animal, four times 

 the natural size. From a specimen in the collection of Thos. Davidson, Esq. 



Thecidium 3Iediterraneum, Sby., Thes. Conch, vii, p. 371, pi. 

 73, fig. 30-32. Lacaze-Duth., loc. cit., p. 262, pi. i — iv. 



This species is found attached to corals in the Mediterranean. 

 It is the T. testudinaria, Michel., and the T. spondylea, Scacchi. 

 It has also been found in Jamaica. 



Thecidium Barretti, Woodw,, Geol. Mag. 1864, i, pi. ii, fig. 1 

 —3. Dav., P. Z. S. 1866, p. 104. 



This species, first described from fossils, has been found living 

 on the coast of Jamaica, at 60 fathoms. 



Family RHYNCHONELLID^E. 

 Genus RHYNCHONELLA, Fischer. 



Fig. 28. Fig. 29. 



Fig. 28. Neural aspect of Rhynchonella acuminata^ fossil, from a cast, show- 

 ing vascular impressions. 



Fig. 29. Umbonal aspect of the same, a, adductor scar; R, cardinal ; p, 

 pedicel ; v, vascular ; o, ovarian impressions. 



RhyncTionella, Fischer, Not. des Fos. du Gouv. de Mosc. 1809. 



