310 Mr. R. Hovvse on the Permian System of the 



26. AxiNus DUBius, Schloth. — Baron Schauroth has recently 

 shown that the specific name duhius, originally applied to this 

 shell by Schlotheim, has priority of all others, even of the now 

 well-known Sowerbian epithet obscurus. It is therefore neces- 

 sary to adopt this so-long-neglected name. 



Under this name there may be very conveniently placed the 

 following species of authors: — Axiniis obscurus, Sow.; A. par- 

 vus, pusillus, pi'oductus, undatus, elongatus, rotundatus, and Lu- 

 cina minima, Brown ; Schizudus Schlotheimi, Geinitz, and Schi- 

 sodus truncatus. King. 



Remarks on Mr. Binneifs Speci?nens. — Two small casts oi Ax. 

 parvus belong without doubt to the above. — A. productus re- 

 sembles the form which King has separated under the specific 

 name truncatus. It is rather more produced in front, and more 

 truncated behind. It cannot claim to be more than a regular 

 growth of dubius. — A. undatus and A. elungatus belong also to 

 the above. They present no peculiar characters. — A. pusillus 

 and Lucina minima appear to be the young of the foregoing 

 species. 



In the ' Perm. Mon./ under four specific names (pi. 15. f. 23- 

 32), are very good representations of some of the forms of this 

 characteristic species ; but the peculiar ornament of the shells 

 of this genus is, I think, not represented. 



In the upper beds of limestone it occurs of great size, some 

 specimens being 2 inches in length. It is rather plentiful in 

 the shell-limestone, and rare in the compact. 



27. AsTARTE ? Vallisnertana, King. — The specimens of this 

 shell which I have collected at Whitley are rather more trian- 

 gular than the figure in the 'Perm. Mou.,^ and very much 

 resemble, both in the general form and ornament of the valves, 

 some young specimens of the recent Venus striatula. The hinge- 

 line is furnished with a deep triangular cartilage-pit, and the 

 character of the superficial ornament is preserved on the casts. 



I am not able to confirm the existence of Astarte Tunstallensis, 

 King, in our limestone ; and as it bears considerable resemblance 

 to the preceding, and is not strongly characterized, its admission 

 into the Permian fauna, as a distinct species, may be safely ob- 

 jected to till less equivocal specimens are obtained. 



The Astarte Vallisneriana occurs in this district in the com- 

 pact-limestone only; and, according to Baron Schauroth, it is 

 found in the equivalent deposit near Gera in Germany. 



28. Myoconcha costata. Brown. — I find nothing in the 

 form of the teeth of this shell that requires it to be removed 

 from the genus Mijoconcha. So far as I have been able to 

 ascertain, there is only one oblique cardinal tooth in the right (?) 

 yalve, which fits into a corresponding depression of the left. 



