132 
NAUTILOIDEA. 
emarginate upon the peripher3\ The septa number about seventeen 
or eighteen in a complete whorl, so that the}’ are not very approxi- 
mate. The siphuncle is central. 
The test is covered with fine lines of growth. 
Remarhs, This species, as observed by M. de Koninck, bears some 
resemblance to Coelonautilus glohatus ; but it difiPers in being much 
broader, flatter, and less globose, and also in having the umbilical 
margins rounded, instead of being angular, as in Sowerby’s species. 
It differs from the Nautilus Chesterensis, with which it was 
associated by de Koninck, in its much larger umbilicus and more 
distant septa, as well as in its less globose form. 
It should be noted that de Koninck’s figures of this species, as 
represented upon plate xxiii, of his work, do not quite agree with 
those of plate xxxi., the former indicating a shell with a smaller 
umbilicus and more tumid whorls than the latter. 
C. Derhiensis has been found at Vise in Belgium in the “ Calcaire 
Carbonifere Supcrieur (Assise vi.),” Avhere it a})pears to be rare, 
since only two examples were collected. 
Horizon. Carboniferous Limestone. 
Locality. Derby. 
Kepresented in the Collection by a single example. 
Coelonautilus Derbiensis^ var. globularis^ Poord. 
1878, Nautilus Chesterensis^ de Koiiiuck, Faune du Calcaire Carboni- 
fere de la Belgique (Annales dii Mus. Roy. d’llist. Nat. de Bel- 
gique, tom. ii.), p. 97, pi. xxiii. ff. 3, a-c (excl. pi. xxxi. ff. 4, a-c). 
Sjy. Char. This variety differs from the species in being less in- 
volute and in having closer septa. If the figures of “ Nautilus 
Chesterensis ” furnished by de Koninck on plate xxiii. of his work 
(loc. cit.) be compared with those on plate xxxi. the difference in 
the amount of involution will be seen. This difference is borne out 
in the specimens which I examined last year in the Royal Museum 
of Natural History in Brussels, through the courtesy of M. Louis 
Dollo, and is I think sufficient to justify the separation of these two 
forms. 
There are two specimens in the Collection representing the variety 
glohulai'is, one of which is from the Isle of Man, but the locality of 
the other has not been recorded. 
The specimen from the Isle of Man consists of the septate part 
of the shell together with a small portion of the body-chamber. 
The shell is very globose, and consists of two or two and a half 
whorls with a very deep umbilicus, the sides of which are sub- 
