OF SOUTHERN INDIA. 321 



b. Sul.family,—MALLETINm. 



5. iV«c?fZ«n«, Conrad, 186? I have not met with the original description 

 of the genus, hut Conrad refers it to the Nuculanid^. In his description of a 

 cretaceous species from New Jersey (Am. Jour. Conch., V, p. 44,) he states that the 

 shell is "not pearly, thin" "teeth angular, and tooth of the posterior line com- 

 plicated;" the form is ovately elongated and inequilateral, the siu'face smooth, 

 beak pointed, sub-anterior ; one of the typical species appears to be the cretaceous 

 N. papyria, Con., from Haddonfield (Am. Jom*. Conch., V, pi. i, fig. 7, and 

 p. 98, pi. is, fig. 25, (lower figure in right corner). 



6. Malletla, Desm., 1832. Shell elongately ovate, compressed, sub-inequi- 

 lateral, smooth, covered with an olivaceous epidermis, interior sub-nacreous ; hinge- 

 teeth thin, denticulated, the anterior much less so than the posterior ; ligament 

 external, elongated; pallial sinus deep; type, 31. Chileiisis, Desm., ( Solenella 

 Nomsii, Sow.). Hanley describes a second species in his Mou. of Nuculid^, 

 M. Ciiniinr/li, from the Falkland Islands. 



7. Neilo, H. and A. Adams, 1857. Shell sub-quadrangularly ovate, inequi- 

 lateral, with the upper posterior margin arcuated, posteriorly sub-truncate, covered 

 with a brown epidermis, anteriorly slightly gaping, inside not nacreous; liiuge- 

 teeth on both sides of the beak denticulated almost with interruption ; pallial sinus 

 deep; ligament external, small; type, N. australis, Q. and Gaim. f N. Cumingii, 

 apud H. and A. Adams). 



Cretaceous species of the Nvcvlat^wje. 



All the recent o-enera and sub-g-enei'a appear to be represented in cretaceous rocks, but the 

 distinction between Nuculaiia and Yoldia can as yet hardly be recorded with great accuracy. 

 The Nuculana usually are small, moderately tumid, rather strongly attenuated posteriorly and 

 flexuously produced; the FortlancUce are also of small size, tumid, and narrowly, but shortly 

 attenuated, and the Told'm are of larger size, very gradually attenuated posteriorly, not mucli 

 produced and slightly flexuous. But unless the examination of the internal structure confirms the 

 determination made according to these external characters, it cannot be looked upon as absolutely 

 correct. A great difficulty exists in tracing out the pallial impression in fossil Nuculana. Whether 

 and which of the European species could be referred to Pernsoaota and Nucularia of Conrad is 

 at present difficult to say, because the genera are not yet sufficiently known as regards the type 



species themselves. 



For reference of a large number of the species here recorded, see Pictet and Campiche, Pal. 



Suisse, III"^ ser., 3"« part., p. 400 et seq. 



1.%—Nicctdana Valaiigiensis, P. and C, N. scapha, d'Orb. 



3._JV^. scaphoicles, P. and C. This extremely resembles, in form and size, the Californian type 

 of cretaceous shells, ca'lled by Gabb MeeUa (see family Trigoxiid.e), but as the hinge of the only 

 specimen of scaphoicles does not appear to have been exposed, it is impossible to ascertain the generic 

 determination of the species. 



4-5.— iV^. lingulata and solea of d'Orbigny belong to the sub-genus Adrana. 



6-11.— iV^. Marice, ^'0\:h., phaseoUna, Mich., Neckeriana, P. and Rous, rihrayeana, d'Orb., 

 angulata',^0^., Ihieala, Sow., (Trans. Geol. Soc, Lou., iv, pi. xvii, fig. 9, and Mem. Cour. Acad. 

 Belg., Fossilesde Bracquegnies par Briart et Cornet, p. 6-3). The two last species recall the form of 

 Porilandia, but they are noted as possessing the pallial sinus entire. 



