OF SOUTHERN INDIA. ISL 
These proportions are as follows :— 
Cryp. pyramidalis, Ner. in Goldfuss. height : diametral width of a whorl (consd. as 1:00) = 0:28 
2 ” ” », Peter’s Fig. 1 AG 5 55 i — 0:98 
” ey) 2” ” ” Fig. 3 39 as ef SS = 029 
This shows clearly the difference between the measurements of Zeuschner’s figures, quoted 
above. ‘The present species had heen first referred by Miinster to the cretaceous deposits of the 
Gosau; its true jurassic position was, however, afterwards recognised through Dr, Peter's 
researches. 
3. Cryptoplocus conieus, Stoliczka, 1867 (Nerinea subpyramidalis, in D’Orbigny’s Pal. franc. 
terr, jur. IT, Pl. 279). There can be no question as to the distinction of this species from Miinster’s 
C. subpyramidalis and Peters very properly remarks, that he is astonished how D’Orbigny could 
identify both. Quenstedt also says that he never met among specimens of WV. depressa and subpy- 
vamidalis any such form as had been figured by D’Orbigny. 
Height : diametral width (consd. as 1:00) of one whorl according to D’Orbigny’s figure... 0°19 
Cretaceous ; 
4. Crypt. brevis, D’Orb. sp. Pal. frane. terr. erét. II. p. 92, Pl. 162, Figs. 3 and 4. 
ay »,  monilifer, D’Orb. sp., ibid. p. 95, Pl. 163, Figs. 4—6. 
6 »  Sancte-Crucis, Pict, et Camp. Mat. p. 1, Pal. Suisse, 3me. ser., p. 260, Pl. 69, Fig. 6. 
7 »  annulatus, Sharpe, sp. Quar, Jour. Geol, Soc. Lond, 1850, VI, p. 112, Pl. XIII, Fig. 
= 
° 
The whorls of this last named species are somewhat concave; Sharpe says, however, distinctly 
“one fold in the interior, on the top of the whorl, curving outwards.” 
We cannot conclude these notes on Cryptoplocus without referring to a few 
very similar forms. 
Piette described in the XII. volume of the Bull. Soe. Géol. de France, 2d. 
ser. p. 1114, Pl. XXXT, Figs. 5-8, a Nerinew patella, which agrees in the form of 
the shell perfectly with Cryptoplocus, but has one fold (tooth ?) on the outer lip. 
D’Orbigny (Pal. franc. terr. jur. IT, Pl. 305, Figs. 6-9) figured a Zrochus mono- 
plicus, which is transferred by Eug. Deslongchamps to Néso (vide Bull. Soc. Linn. 
Norm. V, p. 125, Pl. XI, Fig. 3). Certainly the species is not a Zrochus, but I do 
not think it can be left in the same genus with typical species of Miso, for it 
has one distinct and strong fold on the columellar portion of the inner lip. We 
could quote several other examples, but it will suffice here to show that there are 
fossil forms of shells, which agree in every respect with Cryptoplocus, but some of 
which have one fold on the outer lip and some on the columella. Ought these 
forms to be separated as distinct genera, or ought the characteristics of Cryptoplocus 
to be extended to include them by allowing a change in the place of thefold ? This 
is a point which cannot be properly decided without a close comparison of respect- 
ive well preserved shells, and without knowing the physiological and morphological 
importance of that fold in at least one closely allied genus. We need scarcely 
remark that Cryptoplocus has its nearest ally, as to the form of the shell, in Niso, 
and if some species (as, for instance, C. monilifer) did not exhibit a structure 
of the shell so remarkably similar to that of Merinea and others, we could place it 
among the Huzruipx; or perhaps more correctly place Miso and the allied genera 
here, instead of in the last named family. This only shows the close relationship 
2a 
