OF SOUTHERN INDIA. © 15 
tiary, although this restriction to tertiary beds is not by any means so close as was 
formerly thought by paleontologists. In the Lias the SreHonosromara constitute 
perhaps five per cent. of the Gastropoda, as compared with the Hotosromara. After 
that period, however, their number increases rapidly, and they soon overpower the 
latter to a large extent, being more numerous in the present seas also. 
‘Under this tribe we shall describe the following families in the order here 
quoted. Some of the last named are by other conchologists transferred to the 
Hotostomara. Our reasons will be found stated’with the families farther on. 
1—Ffamily ALATA (comprising the Srrouernz and Aporrnarpm, or as 
proposed s7ROMBINE, TEREBELLINE, APORRHAIN E). 
2. 5 CYPRAIDA (cyprxivz and ovine). 
3 - OLIVIDZ (orrvin# and AancrLLarine). 
A. 43 DOLITD 4. 
5. ae CASSIDID 4. 
6. ey PLEUROTOMID (cLATHURELLIN®, CLAVATULINE and PLEv- 
ROTOMINS). 
7. - CONID ZA. 
8 35 VOLUTIDAi (MARGINELLINZ, VOLUTINZ, VOL UTOMITRINE, 
MITRIN2). 
J). a3 FAS CIOLARIDZA. 
10. a MURICID (FuLreuRInz FUSINE, MURICIND). 
ahs TRITONIDZ. 
ee COLUM BELG ED A. 
6% a BUCCINID 4 (PHOsInz, NASINE, COMINELLINE, BUCCININE). 
14, 35 PURPURIDZ. 
15. 55 TRICHOTROPID. 
16. <3 CANCHELLIARIDA. 
aie 3 TEREBRIDAE. 
18. $5 PYRAMIDELLIDZ. 
19. si CERITHIOPSID. 
20. 3 CHERITHIIDZ. 
I. Family. ALATA. 
In taking advantage of this early name of Lamarck we do not intend to express 
by it more than the simple meaning the word itself indicates, namely, the general 
resemblance among the different forms of the shells in this family as regards the eapan- 
sion of the outer lip. This was Lamarck’s first idea, when establishing the family, and 
so far as any practical advantage is concerned in the determination of shells only, we 
believe, this general idea has not been yet superseded. Much, however, has since 
then been done in the examination of the animals, and, depending on the differences 
