1861.] DAVIDSON BBACHIOPODA, SALT-RANGE. 33 



safest plan will be for the present to consider the Punjab shell as a 

 variety of S. Morrisiana*. 



II. Brachiopoda of the Carboniferous Period, collected in India 

 hij W. Pardon', Esq., F.G.S. 



At Mr. Purdon's request I have examined the Brachiopoda collected 

 by himself during his survey of the Punjab and N.E. Himalayan 

 districts of India. 



Mr. Purdon's collection contained many interesting and fine exam- 

 ples of the following species t : — 



1. Terehratida HimaJaifensis, Dav. ; 2. Athyris Royssii, L'Eveille ; 

 3. Athyris suhtilita,'K'A\\{^^),\ViV. ; 4. Spirif era Moosakhailensis, J)?iY .; 

 5. Sp, lineata, Martin, var. ; 6. Rhynchonella Pleurodon, Phillips, 

 var. ; 7. Camarophoria Purdoni, Dav. ; 8. Streptorhynchus Crenistria, 

 Phillips ; 9. Strept. pectiniformis, Dav. ; 10. Productus striatus, 

 Fischer; 11. P. Cora, B'Orh. ; 12. P. Purdoni, Dav. ; 13. P. costatus. 

 Sow. ; 14. P. Huniholdtii, D'Orb. ; 15. P. semireticulatus, Sow. ; 16. 

 Strophahsia Aforrisiana, King (?), var. ; 17. Aulosteges Dalhousii, 

 Dav.; 18. Crania (sp. undeterminable). 



Having already described the sixteen first-named species in my 

 preceding communication, aU that remains for me to do, in order to 

 complete the notice of what has been up to the present time dis- 

 covered, is to describe the Aulosteges Dalhousii from the very inter- 

 esting specimen found by Mr. Purdon in the Carboniferous (?) rocks 

 of the Punjab. 



AuLOSTE&Es DALHOusn, Dav. PI. II. fig. 7. 



Subtrigonal marginally, wider than long ; anterior angles rounded ; 

 moderately indented in front ; hinge-line slightly exceeding half the 

 ^^'idth of the sheU. Yentral valve convex, divided by a wide and 

 deep mesial sulcus or sinus ; beak nearly straight, but inchning more 

 to the one than the other side ; area flat, irregularly triangular, 

 forming an obtuse angle with the plane of the dorsal valve, and di- 

 vided along the middle by a narrow convex pseudo-deltidium, the 

 entire surface (area excepted) being closely covered with slender 



♦ In 1857 Messrs. Ho wse, Kirkby, and myself entertained the opinion that the 

 British Permian .S'. Morrisiana should be considered identical with the >S. lamellosa 

 of Geinitz, or as notliing more than a variety of it ; but although we are not yet 

 prepared to abandon that view, it must be mentioned that Dr. Geinitz has ex- 

 pressed a contrary opinion in his recently published work, ' Dyas oder Zechst.,' etc., 

 wherein he asserts that .S'. lamelhsa and .S'. Morrisiana are entirely distinct species. 

 It must not, however, be forgotten that *S'. larn/illosa appears to have boen a very 

 variable species, and to have suffered great modifications of general form, mode 

 of growth, and of spine-arrangement, such as changes in physical condition would 

 necessarily induce, and which should never be overlooked in taking philosophical 

 views of species. 



t It was not my intention to liave alluded to the species collected in the Punjab 

 by Mr. Purdon until the publication of that gentleman's memoir upon the geo- 

 logy of the district ; but, as I had also promised Dr. Fleming to describe those he 

 had found m the same localities, I thought it desirable to delay no longer the 

 mention of those collected by Mr. Purdon, and to give him full credit for his 

 discoveries. 



VOL. XVni. PART I. D 



