144 SUPPLEMENT TO THE 



25. Triplesia Wenlockiensis, Dav. Sil. Sup., PI. VIII, fig. 23. 



Shell small, transversely oval ; dorsal more convex or deep than the ventral valve, 

 with a prominent angular fold commencing at about half the length of the valve and 

 widening as it nears the front ; ventral valve convex, with a deep, Avide, angular sinus, 

 also commencing at about half the length of the valve ; beak prominent, slightly incurved ; 

 area triangular, fissure arched over by a narrow deltidium ; surface smooth ; interior not 

 known. 



Length 3|, breadth 4 lines. 



Ohs, — Dr. Callaway informs me that he found one specimen only of this species at 

 Wenlock, in Shropshire. It is, however, somewhat remarkable that out of upwards of 

 fifty or sixty thousand specimens of Brachiopoda obtained by Mr. George Maw from his 

 extensive washings of Wenlock Shales in Shropshire, as well as from his many hand- 

 pickings from the old Wenlock Quarries, not a single specimen of this Triplesia was 

 discovered. I consequently give its position on Dr. Callaway's authority, and it is 

 very desirable that the locality should be searched for more specimens. 



Triplesia is usually found in rocks a little older than the Wenlock, but Dr. Hinde 

 assures me that he procured a specimen of a species nearly related to Triplesia insularis 

 from a rock of Wenlock age in the Island of Anticosti (Canada). 



26. Triplesia Gray^, Bav. Sil. Mon., PI. XXIV, figs. 31—32 ; PI. XXV, figs. 9—11 ; 



and Sil. Sup., PI. VIII, fig. 32. 



The exterior of this remarkable species was fully described at p. 198 of my ' Silurian 

 Monograph.' Mrs. R. Gray informs me that notwithstanding the most diligent search, 

 not more than half a dozen complete specimens had previously been found in the 

 Girvan district. A few bivalve examples had been collected at Craighead, and detached 

 valves in the Balcletchie conglomerate in Strata of Upper Llandeilo age. 



No specimens showing the interior of the valves nor any internal casts have yet been 

 discovered. They should be sought for in the localities where the shell occurs. 



