﻿156 Proceedings of the Royal Physical Society. 



preserved pedicle-valves are in the collection, so that the 

 presence or the absence of a median septum cannot be 

 ascertained ; it is therefore not possible to say, with cer- 

 tainty, whether we are dealing with a Derhya or with an 

 Orthotetes. So far as external characters can be trusted, it 

 appears to be closely allied to, if not identical with, the 

 form described as Streptorhynchiis crenistria'' (Phill.) by 

 Professor Toula.^ In common with it, the brachial valve, 

 broad and convex, has a shallow median depression, and its 

 ornamentation is the same. 



Spiriferidae. 



PtETICULARIA, M'Coy. 



Reticidaria lineata (Martin). 



This determination is based on the external characters of 

 one specimen only, but as both the shape and the ornamenta- 

 tion of the shell are quite typical, little doubt need be enter- 

 tained as to the validity of the identification. 



Productidse. 



Maeginifera, Waagen. 



Marginifera, sp. indet. 



A large Productoid shell, four inches in width from wing 

 to wiug, is to be referred to this genus. Although too 

 imperfectly preserved to justify a specific determination, 

 it exhibits the generic character distinctly enough. The 

 brachial valve being much corroded and partly broken, the 

 shelly ridges or shelves situated within the wings in the 

 pedicle-valve are exposed to view ; the brachial valve is too 

 weathered to show the corresponding ridges along the shell 

 margin. 



This form is characterised by a very much inflated pedicle- 

 valve, forming a regular spiral curve in the longitudinal 

 direction. The apex is prominent, and near it there begins 



^ " Kohlenkalk Fossilien von der Siidspitze von Spitzbergen," SUzh. K. 

 Akacl. Wiss. Wicn., Math. Nat. CI., Ixviii. Bd., 1873. 



