NArilLID^. 
109 
Ireland, some were found to exhibit upon the cast of the body- 
chamber distinct marks of the shell-muscles. In one specimen 
(Xo. 50190) these are so perfect as to give a very clear outline of 
their form ; and some of the test having been removed, their entire 
course can he made out. 
Fig. 15 {A, B, D) shows the appearance of these muscular im- 
pressions, carefully drawn, from this specimen. 
A dra^ving has also been made (fig. E), much reduced in size, 
from a cast of the interior of the shell of XautUus pompiliiis, in 
order that the muscular impressions of C. cariniferiis might be 
compared with those of existing species of Xautilus. 
Fig. D represents the specimen selected for illustration, it is 
reduced in size from the original about one half. The portion 
marked with the letters p, rn was removed from the rest of the 
shell in order that the muscular impressions might be drawn as 
seen in figs. A and B, which are of the actual size. 
Fig. is taken from a larger (probably adult) specimen of C. 
cariniferiis (“ Sowerby Collection,’* Xo. 43801), and shows the 
marks of the shell-muscle on one of the angles of the whorl more 
distinctly than they can be seen on the smaller one. 
A more detailed description of the figures may now be given. 
Fig. yi represents the ventral or peripheral side of the base of the 
body-chamber. The impressions of part of the shell-muscles are 
seen at ?a, m, while indicates their rugose and pitted surface, 
showing how strongly they were attached at the angles of the whorls : 
this is further evidenced by the deep groove gr. in fig. C. 
Connecting the broader portions of the muscular impressions is a 
narrow band, near the centre of which is a little shallow pit 
(fig. A), which undoubtedly formed part of the muscular system, as 
the narrow band is slightly enlarged at this point to embrace itk 
Fig. B is the underside of A. On this side it will be seen that 
the narrow hand at its central part is strongly deflected backwards, 
in a similar manner to that of the annulus of the recent jVaufilus 
(xV. ponipilius), so well figured (pi. xxxix. fig. 4) by Dr. W. Waagen 
in his well-knowui memoir entitled “ Ueber die Ansatzstelle der 
Haftmuskeln beim Xautilus und den Ammoniden”^ 
The deflected portion bears several shallow^ more or less elongated 
pits, w’hich seem to indicate a rather strong attachment of the 
muscles at this point, though not so strong as at the angles of the 
whorls, where the muscular impressions are broadest. 
^ This enlargement is not indicated in the figure, as it should have been. 
^ PaliBontographica, Bd. xvii. 1870, p. 185, pis. xxxix. & xl. 
