546 MM. Foord and Crick — On Nautilus elegans, Shy. 



the JV. elegans of Sowerby, before be was aware tbat Pictet l had 

 already pointed this out. 



With Sowerby's Nautilus elegans bas often been confounded the 

 Nautilus pseudoelegans of d'Orbigny. The true characters of the 

 latter species we have been able to observe from two specimens, 

 which Dr. Paul Fischer, of the Museum of Natural History, Paris, 

 very kindly sent to one of us from the d'Orbigny collection. One 

 of these is figured in Fig. 3. The species is readily distinguished 

 from Nautilus elegans by its much thicker and more robust form, 

 closer septa, the position of its siphuncle, and the coarser character 

 of its ornaments. It is also met with at a lower horizon, both in 

 England and France, than Sowerby's species. From N. Atlas it 

 differs in the broader periphery, open umbilicus, closer septa, and 

 position of its siphuncle, which is near the inner margin of the septa, 

 instead of the outer, as in N. Atlas. The ornamentation of the test 

 is also much finer in the latter than it is in the present species. 

 The JV. pseudoelegans referred to by English geologists is probably 

 that of Sharpe, which has been shown above to be Sowerby's N. 

 elegans. 



According to MM. Pictet and Campiche 2 N. pseudoelegans presents 

 some variations in the Sainte-Croix specimens, those authors dis- 

 tinguishing four distinct types, of which they give figures (plates 

 xiv. and xiv. bis of the work cited above). The first of these types, 

 which is from Yonue, is remarkable for the smoothness of the test 

 in the young shell ; the second, from Sainte-Croix, differs very 

 little from the first, being only slightly more compressed. The 

 third type scarcely differs at all from the two preceding ones. In 

 the fourth some slight variations in the position of the siphuncle 

 are noticed. In the Indian examples of the present species figured 

 by Blanford the ribs are much coarser than they are in the 

 English specimens, and indeed on comparing the specimens from 

 the d'Orbigny collection with Blanford and Stoliczka's 3 figures and 

 descriptions there is reason to doubt the identity of the Indian 

 with the European forms, although the two forms are nearly related. 

 Blanford's description of the species is as follows : — " Shell inflated, 

 evenly rounded, ornamented with numerous sulcations generally 

 visible on the cast. Ventral area broad and rounded. Umbilicus 

 impressed and very small in the cast ; the perforation not exceeding 

 -A- of the diameter of the shell. The sulcations rather variable in 

 width, narrow on most specimens, forming a very obtuse angulation 

 on the median ventral line, whence the sulci curve forward towards 

 the umbilicus (generally becoming obsolete on the sides of the cast), 

 and forming a very slight flexure towards the umbilicus. Aperture 

 orbicular ; septa numerous, about 22 to the whorl, the margins 

 [sutures] slightly flexuous at the sides, straight or slightly convex 



1 Descr. des Foss. du Terr. Cret. des Environs de Sainte-Croix (Pal. Suisse), 

 ser. ii. pt. i. 1859, p. 117. 



2 Ibid. pp. 123-128. 



3 Mem. Geol. Surv. of India — Palseont. Indica — I. Cretaceous Cephalopoda of 

 Southern India, p. 33, pi. xvii. f. 3, pi. xviii. ft 3, 3a, 3b, pi. xix. pi. xx. if. 1, la. 



