OP SOTJTHEEN INDIA. 149 



Thus Homer's divisions are evidently not yet completed, and it is impossible 

 to predict how the author will finally treat the subject in his large Monograph, the 

 papers in the "Mai. Blsetter" being only preliminary. Every one who looks over 

 the numerous species which in H. and A. Adams' '' Genera/' for instance, have been 

 referred to Chione as a genus, must admit that there is a great variety of form 

 among them, distinctly indicating many very good sub-divisions. Homer's anom- 

 alous treatment of our nomenclature is, however, in any case quite objectionable ; 

 the introduction of distinct names for every section is not justifiable. I believe 

 that those peculiar forms, if they are at all definable, ought to be designated as 

 separate sub-genera of Venus, but we ought not to go beyond this already tri- 

 nominal nomenclature. 



QcL Anaitis, Eomer, 1857, (Krit. Untersuchimg, &c., Oassel, and Mai. 

 Blsetter, xii, p. 153, &c.). This ought to include the moderately tumid cordate 

 forms with strong concentric lamellae ; the hinge is not different from that of true 

 Venus, except that the anterior teeth are more elongated and more regular, as in 

 Chione, Homer, in 1857, distinguished two sub-genera (?), Clausina, Brown, and 

 CMone, Miihlf., quoting V, thiara., Dillw., as the type of the former and V. plicata, 

 Gmel., as that of the latter; the first is stated to possess a small triangular, the 

 latter a roundish triangular pallial sinus. In the later review of the species he 

 does not consider the distinction of the two sub-genera (or sections) necessary. 



Qe. Gompliina, Morch, 1855 ? Shell ovate, cordate, moderately inflated, 

 smooth; hinge-teeth the same as in typical Chione, Homer describes four species, 

 and considers V, undulosa, Lam., as the type, while H. and A. Adams quote 

 Venus donacina, Chem., as the only species, and place it as a sub-genus of Cytherea 

 f=: Meretrix), 



Gemma, Deshayes, (type V, gemma, Tott.,) ought, I think, to be transferred 



to the I)08INIIN2E, 



7. Fsephis, Carp., 1865, (Proc. Acad. Nat. Sc, Phil., for 1865, p. 56). This 

 is based upon a species described as Chione Lordi in Proc. Zool. Soc, London, for 

 1863, p. 69. There are three elongated and thin cardinal teeth in each valve; the 

 shells are rather thin, roundish, or quadrangular, and somewhat inflated, pallial sinus 

 small ; the animals are oviparous, like Sphcerium, In Journ. de Conch., vol. xiii, 

 1865, p. 135, a second species, Fs, tellimyalis, from California is described by the 

 same author. The former species also occurs in young tertiary deposits of 

 California, and Gabb adds to it Ven. tantilla, Gould, also living and "post- 

 pliocene" (vide Palseont. Calif., vol. ii, p. 96). The form and general character 

 of the type species is said to be between Fachydesma and Circe, 



8. Cytherea, Lam., 1805,* fMeretrix apud H. and A. Adams and Chenu). 

 Homer (Monog. der Moll. Venus, Linne, 1864 pp. 1, &c.,) considers Cytherea as 



^ I adopt here tlie name Cytherea, Lam., in preference to that of Meretrix of the same author for reasons which 

 are well known to every conchologist. The name has been for the last 60 years so thoroughly associated with the study 

 of recent and fossil shells that I do not see the slightest advantage in replacing it by the older name Meretrix, thouo-h 

 I could not argue with Deshayes that no one has a right to introduce a name which was given up by the author himself 



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