APPENDIX. 21 



Rhynchonella. 



I have little to add regarding the species belonging to this genus, although several alterations will 

 probably be required as we progress in the knowledge of the variations peculiar to each of the species. 



Page 69, Rhynchonella Wrightii, Dav. 



In 1852 a single example of this remarkable species had been discovered ; but since then three more 

 have been collected by Dr. Wright, one of which I have represented in PL A, fig. 17; and among 

 several Terebratulae found by M. L. Saemann, in the Inf. Oolite of the Department de la Sarthe (France), 

 I was glad to recognise our British species. 



Page 90, Rhynchonella obsoleta, Sow. 



During an investigation of the Linnean Collection on the 15th of August, 1853, Mr. Salter and myself 

 came to the conclusion that this is the shell to which Linnaeus had applied the name Anomia farcta. His 

 original specimens, (as seen in box 199 of that Collection), were no doubt procured from England, and agree 

 with his description of the species. The oldest name for this shell would therefore be Rh. farcta, Linn. Sp. 

 (' Systema Naturae,' 12th ed., vol. vii, p. 163, 1768); but, as Sowerby's denomination is completely 

 familiarised by constant use, I do not think it would be serving science to restore the Linnean appellation. 



Page 92, Rh. Morieri, Dav., 

 May perhaps be nothing more than a variety of R. obsoleta. 



Page 93, Rh. tetrahedra, Sow. 



It has been found necessary to remove from this species the specimen PL XVIII, fig. 10, which has 

 been considered the type of our Rh. sub-decorata. 



Page 97, Rh. Hopkinsi, M'Coy. 



In PL A, figs. 20 and 21, I have represented two of the four examples preserved in the Cambridge 

 Woodwardian Museum, and stated to be from the Great Oolite of Minchinhampton. Professor Sedgwick 

 believes them to be from that locality, although not of his own collecting ; but it would appear almost certain 

 that the shells in question are in reality not British, and that they were derived from the Great Oolite of Marquise, 

 near Boulogne-sur-Mer (France), — an opinion entertained both by Mr. Bouchard and Mr. Lycett. The 

 last-named gentleman has never seen a trace of such a shell in the oolites of Gloucestershire ; it will, 

 therefore, be necessary (until further proof) to remove Rh. Hopkinsi from the list of British fossils. 



ADDITIONAL SPECIES. 



Rhynchonella sub-decorata (Dav.), Part III, PL XVIII, fig. 10, and Appendix, PL A, figs. 23 — 26. 



,, tetrahedra (part), Davidson, 'Mod. of British Oolitic and Liasic Brach.,' p. 95, 



PL XVIII, fig. 10, 1852. 



Diagnosis. Shell obtusely deltoid ; wider, but almost as deep as long ; dorsal or socket valve much 

 inflated and contracted at the umbo, whence it presents a longitudinal mesial curve, rising at almost 

 right angles to the direction of the opposite valve, and attaining its greatest elevation near the front. 



