G. C. Crick — On Gomatites, Nautilus, etc. 



417 



passing from the inner side obliquely backwards to the outer, but on 

 the second third of the first whorl these transverse lines are crossed 

 by longitudinal lines, so that the latter are distinctly crenulated. 

 They cover the lateral area, and increase in strength as they approach 

 the outer portion of the whorl. These ornaments on the lateral 

 area gradually become fainter; at about the middle of the second 

 whorl the transverse lines are much finer, and only a few of the 

 longitudinal lines remain near the periphery, and these are very 

 faint ; at the extremity of the specimen only exceedingly fine lines 

 of growth are present. 



SUBCLYMENIA EVOLtlTA, J. Phillips, Sp. 



a, lateral aspect ; b, peripheral aspect ; c, front view with the outer portion detached, 

 showing' the position of the siphuncle and the peripheral lobe of the suture-line as it 

 appears nearly at the end of the first whorl. Carboniferous Limestone : locality 

 unknown. 



Drawn from a specimen in the British Museum (Natural History), No. C. 5336. 

 Natural size. (The specimen is quite symmetrical, although it scarcely appears to 

 be so in fig. c, owing probably to the piece of matrix adhering to one side of the 

 fossil and covering not only the lateral area of the whorl, but also a narrow portion 

 of the periphery.) 



The oi-naments on the periphery at the middle of the first whorl 

 consist of about six longitudinal strias near each margin, diminishing 

 in strength from the angular margin inwards, crossed by exceedingly 

 fine transverse striae, which in passing from the lateral angles cross 

 the longitudinal striae obliquely backwards, becoming on the mediau 

 portion of the periphery more pronounced and forming a wide deep 

 sinus concave forwards. As the shell increases in size, the longi- 

 tudinal almost obliterate the transverse lines ; while the ornaments 

 on the median portion become very distinct, and are also crossed by 

 very fine, obscure, longitudinal striae. At the extremity of the speci- 

 men the longitudinal lines near the margins are more pronounced, 

 and the central curved lines almost-obliterated. The central area is 

 slightly raised above the i - est of the periphery, and is feebly concave. 



The first suture-line is only slightly backwardly curved on the 

 periphery, and the three following suture-lines have merely a very 

 shallow, simply curved, peripheral sinus ; but at the middle of the 

 first whorl the suture-line has a distinct V-shaped peripheral lobe, 

 and is on the whole almost similar to that of the adult shell. 



DECADE IV. VOL. III. NO. IX. 



'27 



