284 NEW UNIONIDiE, MELANID^, ETC., 



mide tenebroso-fusca, eradiata, marginata; dentibus cardinalibus sublongis, subobliquis, creuula- 

 tis, lamellatis, in utroque valvule duplicibus ; lateralibus prEelongis, obliquis, lamellatis corrugatis- 

 que ; margarita alba et valde iridescente. 



Shell plicate, wide, inflated towards the beaks, very inequilateral, acutely angular 

 behind and rounded before ; valves rather thick, thicker before ; beaks rather promi- 

 nent and slightly plicate; epidermis dark brown, without rays, bordered ; cardinal 

 teeth rather long, somewhat oblique, crenulate, lamellar and double in both valves ; 



suggested by these gentlemen that, 'perhaps from not knowing the shell (Douglasias) as figured in Griffith,' I 

 had ' described and figured Murchisonianus, which there is no doubt is the Souglasice of Gray.' In answer to 

 this I would ask how I could, when I read my paper on the 16th March, 1832, before the American 

 Philosophical Society, know of a description in GriSith's Cuvier dated 1834 (not in 1833, as incorrectly cited) ? 

 DouglasioB therefore cannot have precedence ' of some years,' as claimed for it, but it must remain a synonym 

 to Murchisonianus, where I placed it in my Synopsis, first, second, and third editions, since 1836. 



" As regards the claim in the same paragraph for U. Shanghaiensis, Lea, being also a synonym to 

 Douglasice, I am constrained to differ in opinion. Slianghaiensis is not the same with Douglasicef^s affirmed, 

 but it is the same with TJ. OsbecJcii, Philippi, the description of which I had not seen. ' Conchylien, vol. 3d.' 

 Some years since I placed it as a synonym to Osheclcii in the manuscript copy of my Synopsis, 4th edition, 

 preparing for the press. 



"2d. Anodonta tenuis. Gray, — also called Unio tenuis, Gray, in Griffith's Cuvier, — is considered to be, by 

 Messrs. Baird and Adams, an Anodonta, and it is said to be little known. This shell does not belong to 

 either of these genera. It is a true Dipsas of Leach, and if Dr. Gray had had a perfect specimen before him 

 when describing Anodonta tenuis, he never would have placed it in that genus. The JDipsasian character was 

 evidently obliterated by age in the specimen from which he made his diagnosis. The young specimens, and 

 the mature perfect ones, always have the tooth (so to call it) of the genus Dipsas. I described this species in 

 the Transactions of the American Philosophical Society, March 15th, 1833, under the name of Symphynota 

 discoidea, with a figure perfectly representing the characteristic tooth, which consists of a single raised, 

 slightly curved line under the dorsal margin. In my 'Synopsis,' in the first edition in 1836, as well as in the 

 second and third editions, I gave Dr. Gray's tenuis as a synonym to this shell, which I there placed in the 

 genws Dipsas, where it properly belongs. It must therefore stand as Dipsas discoidea, Lea, with the synonym 

 o{ Anodonta tenuis, Gray; my date being 1833, and Dr. Gray's 1834. 



" In this paper of Messrs. Baird and Adams, they have described a supposed new species from Shanghai, 

 under the name of Unio (Lampsilis) subtortus. I previously published a description of a species which I 

 believe will prove the same, under the name of tortuosus, in the Proc. Acad. Nat. Sci. April 18, 1865. Since 

 then I have found in the 'Journal de Conchiiiologie,' July, 1863, — which work for that year was not accessible 

 to me, — that Messrs. Crosse and Debeaux had given a description and an e.xcellent figure of a Unio of the 

 same twisted character, under the name of Tientsinensis, which, if the figure be entirely correct, differs in the 

 form of the posterior slope, and in the undulations of that part. 



"I may be permitted to express my surprise that neither the French nor the English authors should have 

 observed the very remarkable character of these Chinese species, which were before them, in being 

 inequivalve ! The figure in the Journal de Conchyliologie seems to be very correctly delineated by the artist, 

 having represented the inequivalve condition of the right and left valves. 



"Messrs. Baird and Adams refer to Tientsinensis, but consider it to differ in some respects from their 

 subtortus. which I think very likely If Tientsinensis prove to be the same as tortuosus and subtortus, then 

 the two last must be synonyms. If not, then there will be two species, viz.: Tientsinensis, Grosse and 

 Debeaux, and tortuosus (nobis), — subtortus, B. and A., being a synonym to tortuosus." — {Proc. Acad. Nat. 

 Sci. April, 1868 ) 



