BRITISH DEVONIAN BRACHIOPODA. 39 



cated with me on the subject, I sent him a larger specimen of the same shell, and this 

 I have drawn (Dev. Sup., PI. I, fig. 10). 



Glassia WJddbornei is the largest of the three species of the genus with which we are 

 at present acquainted, and its shape and the arrangement of its spirals resemble more 

 those of Glassia elongaia than G. olovata, which are both from the Upper-Silurian rocks 

 of Shropshire. We are now acquainted with the genus, therefore, both from the Upper 

 Silurian and Middle Devonian. 



Glassia Whidbornei occurs in the Middle-Devonian limestone at Lummaton, near 

 Torquay ; and I have much pleasure in naming it after Mr. G. F. Whidborne, who has 

 zealously assisted Mr. Glass and myself by placing his entire Devonian collection at our 

 disposal, and in liberally allowing Mr. Glass to operate upon any of his specimens. 



Genus — Atrypa, Balman, 1828. 



27. Atrypa reticularis, Linne. Dav., Dev. Mon., PI. X, figs. 3, 4 ; and Dev. Sup., 



PI. I, fig. 16. 



At page 53 of my ' Devonian Monograph ' I described the exterior character of this 

 species, and gave a figure of its vertical spiral coils. At that period the connections of 

 the spirals had not been worked out, nor even discovered, hence my figure in that respect 

 was incomplete and defective. Since then all the characteristics pertaining to the genus 

 and species have been fully elaborated, and will be found described in my Silurian Supple- 

 ment. Some few remarkably well- weathered specimens, and sections of the shell, with 

 the edges of the spiral coils sharply defined and projecting, have been picked up at Hope's 

 Nose by Mr. Whidborne, and of one of these a figure has been added to this Supplement. 



28. Atrypa desquamata, /^owj., sp. Dav., Dev. Mon., PI. X, figs. 9 — 13; PI. XI, 



figs. 1—9 ; and Dev. Sup., PI. I, figs. 15, 15«. 



Since I described this fine large species at page 58 of my ' Devonian Monograph ' 

 Mr. Glass has been able to develop in the most complete manner the attachments of the 

 principal lamellae to the hinge-plate, the spirals, and their connection or loop. In my 

 Monograph I described A. desquamata as a distinct species with some uncertainty, but 

 both Mr. Whidborne and myself have observed such a difference in the young specimens 

 of the two forms — the broad hinge-line, median depression, and fine striation in A. desqua- 



