OF SOUTHERN INDIA. 105 



I have already alluded to the great similarity and relation between the shells of 

 the Faphiid^ and those of the lutraeiin^^ a relation pointed out long ago by 

 Deshayes. The internal cartilage and the lateral teeth of many forms are no 

 doubt closely allied to those of JDarinia and Ccecella, but the peculiar short 

 A -form tooth in front of the cartilage-pit, so characteristic for all Mactrib.¥., is 

 never present in the JPatkiibm, although one of the cardinal teeth, the posterior, 

 in the right valve is generally shorter and more prominent than the other. The 

 smallness of the pallial sinus, or its entire absence, also reminds one of the 

 genera Ccecella and Anatinella. 



Gray first referred three genera to the family- JPaphia, Anapa, and JErmlia ; 

 all three are now admitted by Deshayes in his 2nd edit, of the Paris fossils 

 as good genera. H. and A. Adams have, I think, in this case carried the generic 

 division too far ; it is, to say the least, impossible for any one not having the 

 types of the various generic divisions before him to understand what their real 

 characteristics should be. I shall here retain some of H. and A. Adams' genera 

 only as sub-genera. 



1. Ervilia, Turton, 1822. Transversally oblong, moderately solid, hinge 

 with two cardinal teeth in each valve, and in the left valve of some species with 

 a small additional anterior tooth situated quite close to the lunular margin; 

 pallial sinus distinct. 



2. Anapa, Gray, 1840. Shell sub-trigonal, ventricose, truncated behind; 

 lateral teeth sub-equal, compressed, smooth; pallial line entire; tj^Q A. cuneata, 

 Desh. ; most of the species are from New Zealand. 



2a, The Phillippine species of a more oval or rounded and compressed form, 

 like A. crassula, Desh., were named by Gray Davila, which ought to stand only 

 as a sub-genus of Anapa, 



I may notice here the similarity of the shells of Anapa and Gnathodon, and 

 it is possible, when the animals of more species have been examined, that both 

 genera may be classed in the same family. It is also worth mentioning the remark- 

 able relation of some of the shells of Crassatella to those of Anapa. 



3. Faphia, Lam., 1799, (Mesodesma, Desh., 18e30). Shell sub-trigonal, trans- 

 versally oval, sub-equilateral, or with the posterior part a little shorter, central teeth 

 simple, partially very small, lateral teeth more or less prolonged, the anterior 

 generally shorter than the posterior, pallial sinus small, angular. 



H. and A. Adams separate Taria as a sub-genus of Faphia, and consider 

 Deshayes' Mesodesma (including M, mactroides, Desh. and oth.) and Lamarck's 

 JDonacilla (with the type species D. cornea, Poli,) as genera, but I do not think 

 there is sufficient distinction in the character of those shells to justify that separa- 

 tion. Some of the oblong forms of these so-called Mesodesma and JDonacilla could 

 perhaps, for sake of convenience, be grouped in a special section, but it is impossible 

 to characterize the shells so as readily to distinguish them from those referred to 



Faphia proper. 



2 c 



