DAVIDSON ON SOME FOSSIL BRACHIOPODA. 



471 



"^1 Tre:\iato'5Pir4. H?11 ? ) I c^o not possess material to enable me to illustrate 

 22*. NucLEOSPiHA^Hali?" \ J^^ff genera? but it is to be presumed that Mr. 



) Hall will, ere long, supply this deficiency. 



23. Uncites gryphvs, an imperfect representation of the interior of a portion 



of both valves, showing the position of the pouch -shaped expan- 

 sion ig), and the attachment of the lamella, which are supposed 

 to have formed the spiral cones. A fragment has been added 

 from another specimen, in which are seen traces of spiral 

 lamellte ; but a more perfect representation of these processes, 

 and of the muscular impressions in both valves, has still to be 

 produced. 



24. ,, gryphiis. Profile view of the same, a portion of the shell having been 



removed, so as to show that the pouch-shaped depressions did 

 not communicate with the interior of the shell. 



25. „ gryphiis. A specimen to show that in the young state the shell was 



moored to marine objects by the means of a peduncle issuing 

 from a perforation or foramen in the beak of the ventral valve. 



26. Atrypa, Dalman::=SpmiGERiNA, d'Orb, reticularis, Linnseus. Interior of the 



dorsal valve, showing the natural position of the vertical spiral 

 cones, 



27. „ Interior of the ventral valve, F, foramen ; D, deltidium ; T, teeth ; 



A, adductor or occlusor ; R, ventral adjuster muscular impres- 

 sions, 



28. Specimen from which the larger portion of the dorsal valve 

 has been removed in order to show the back of the spiral cones. 



29. ., Interior of the dorsal valve, from which the spiral lamellae have 



been removed, so as to exhibit the impressions of the ad- 

 ductor or anterior and posterior occlusor muscles. 



30. Anoplotheca lamellosa, Sandberger. Fragment showing the vertical spiral 



cones. 



31 . „ Internal cast of the dorsal valve. A, impressions left by the 



adductor or anterior and posterior occlusor muscle ; J, cardinal 

 process. 



32. „ Internal cast of the ventral valve. Figures, 30, 31, and 32 are 



taken from Dr. Sandberger's Paper, published in 1855 by the 

 Academy of Vienna ; but it is to be regretted that the material 

 hitherto discovered has not enabled the proposer of the genus to 

 give us a more perfect representation of the spiral appendages. 



33. Davidsonia Verneuilii, Bouchard. Interior of the dorsal valve (enlarged). 



J, cardinal process ; if, sockets ; A, A, impressions left by the 

 adductor or posterior and anterior occlusor muscle. A restored 

 representation of the spiral lamellae recently discovered by 

 Prof, de Koninck has been added on one side. 



34. „ Verneuilii, Interior of the ventral valve, showing the teeth, pseudo- 



deltidium, adductor and divaricator muscular impressions, as well 

 as the massive cones and vascular impressions. 



35. KoNiNCKiNA Leonhardi, Wissman, A translucid specimen made thinner by 



acid, and seen from the exterior of the ventral valve, by which 

 means the position of the spiral lamellse has become visible. 



36. „ Leonhardi. Interior of the dorsal valve, with a portion of the spiral 



lamellaa preserved. These two illustrations are taken from 

 drawings sent me by Prof. Suess. 



Note. — Since the publication of the tenth No. of the Gteologist, I have received, 

 through the kindness of Mr. Burrow, of Settle, in Yorkshire, a great number of frag- 

 ments of Cyrtina septosa, and was happy to find among them the internal cast of the 



