366 JOURNAL OF CONCHOLOGY, VOL. lO, NO. 12, OCTtlKfek, l^Oj. 



Assimiiiea Leach in Fleming.— The Rev. G. A. F. Knight's 

 explanation^ of the origin of this name is so entirely satisfactory 

 that I consider the name should be emended to Assemania? The 

 differences in spelling quoted were obviously due to mistakes in read- 

 ing Leach's uncertain handwriting with which Gray may not be 

 entirely unconnected. 



CycJostoma having, as pointed out by Mr. R. B. Newton,'' been 

 twice over used by Lamarck for marine shells before it was employed 

 by Draparnaud for the Nerita elegatis Miill., the name must be 

 abandoned in favour o{ Poviatias Studer, 1789. 



As regards the specific name for our sole British representative of 

 the genus, Mr. Kennard and I have lately used reflexiis (Linn.), 

 following the evidence of Hanley that a specimen was the sole 

 occupant of the tray so marked in the Linnsean collection. This, 

 however, as we have seen in other cases is not good or reliable evidence 

 and the name has only been employed doubtfully by Olivi and quoted 

 in synonymy but not accepted by DaCosta and by Forbes and Hanley. 

 Hence it seems wiser till, if ever, more direct evidence of what Linne 

 really meant is produced to retain Miiller's name, elegatis, for the 

 species. 



Unio. — The author of this genus is Retzius, who wrote the thesis in 

 which it is described, and not Philippson who merely got his degree 

 for defending in public that portion of the thesis, another student 

 being equally nominally responsible for the next section. The rule in 

 those days was for the Prseses to write the thesis : on those rare 

 occasions in which the student himself wrote it the fact was always 

 noted either on the title or in the Praeses' preface. 



Ajiodonta cygncea. — Isaac Lea himself, who made more species of 

 Unionidse than Locard and Drouet together, could only recognise 

 one European species of Anodonta, and until someone can point out 

 a genuine and fundamental anatomical difference between any of the 

 innumerable "species" founded on mere shell variation it is perfectly 

 absurd to recognise more than the one species. 



Sphcerium as a generic name, as well known, predates CycJas. The 

 latter was first used by Lamarck on plates of the " Encyclope'die 

 Methodique," 1798, for a miscellaneous collection of bivalves, but the 

 following year, 1799 {Mem. Soc. Hist. Nat. Paris., p. 84) he again 

 employs the name Cyclas, giving as sole type ^\Teliina cornea Lin." 

 This, to our way of thinking, precludes the use suggested by Uall 

 {Proc. Biol. Soc. Washingto7i, xvi., p. 8) of the name Cyclas for Venus 

 islandica of Linne on the authority of Link, 1807. 



1 /. Cofich., vol. 9, p. 275. 



2 E.g. — Just as Dreissena was emended to Dreissensia when the error was detected. 



3 A7in. and Mag., Nat. Hist., Ap., 1891, p. 345. The name Hartmannia proposed by Mr. 

 Newton in lieu of the later Pomatias Hartmann, appears to be a synonym for Cochlostoma Jan. 



