40 THE BKACIIIOPODA. 



40. — ElIYNCHONELLA FoRBESII, DaviclsOU. 



1857. EuY^•CIIONELLA FoRBEsii, Davidson, Britisli Bracli. Palseont. 



Soc, plate xvii., fig. 19. 

 1877. ,, FoRBEsii, Davidson, Proceedings Dorset 



Field Club, plate iv., fig. 15. 



A peculiar globular little shell characteristic of the Sowerbyi 

 zone. The type specimens figured by Mr. Davidson were round 

 and globular, but specimens occur, especially near Gorton 

 (Somerset), which are more or less flat with a slightly raised 

 fold. This species is well distributed all over this district, 

 in fact occurring wherever the Sowerbyi zone is exposed. It is 

 always small, but could not possibly be taken for the fry of any 

 other species. 



Dimensions. — Length, 5^ ; breadth, 5 ; depth, 8^ lines, and of 

 a flat specimen — Length, 4 ; breadth, 4 ; depth, 1^ lines. 



Localities. — Bradford Abbas, Halfway House, Stoke Knap, 

 &c. (Dorset), near Gorton (Somerset). 



41. — Ehynchonella spinosa, Sclilothem. 



1851. Ehynchonella spinosa, Davidson, British Brach. Palajont. 

 plate XV., figs. 15-20. 



1877. ,, spinosa, Davidson, Proceedings Dorset 



Club, Vol. I., plate vi., fig. 19. 



This species has always a raised mesial fold, the sides of which 

 slope quite gradually. This is a good distinctive feature, and is 

 peculiar to even the finer-ribbed varieties of Rhjnch. spinosa. 

 This species seems to begin in the Humphriesianum zone, in 

 which bed it is rather rare. It ascends into the zone of Parkin- 

 soni, in which it is abundant, and, I believe, goes much higher. 

 Specimens often occur shewing the entire spines more or less, and 

 these can be well worked out with the aid of some very dilute 

 hydrochloric acid. A fine example shewing the species is 

 figm-ed by Mr. Davidson, Palaont. Soc. Journ., plate xv., fig. 15. 



