130 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



whicli expands in the vicinity of tlie apertnre in such, a manner as to show that its 

 margin had the spout-hke projection which is one of the characteristics o 

 Solenocheilus. 



I have described this individual somewhat in detail in order to point out how 

 completely rock-pressure may transform a fossil so that it may, as in the present 

 case, put on a shape which is quite foreign to its normal one. 



Localities. — Little Island, near Cork ; Ireland (precise locality unknown ; this 

 is the type specimen in the British Museum). 



Solenocheilus ? clausus, sp. nov. Plate XXXVI, fig. 8. 



Description. — Shell (known only in the adult stage) nautilus-like, inflated, with 

 rapidly expanding whorls, the inner ones concealed by the last one. The sides 

 broad, somewhat compressed, and merging in the widely rounded periphery. The 

 outline of the aperture, which is only partially preserved, forms a broad curve at 

 the sides, and where it meets the umbilical margin is reflected inwards, forming a 

 flattened, slightly concave, thickened band (callus), which enters and closes the 

 umbilicus. 



The sutures, of which only five are seen owing to the presence of the test, are 

 rather widely separated from each other. Measured from the last they ai-e 

 respectively 15 mm., 15 mm., 14 mm., and 12 mm. apart. The siphuncle is not 

 seen. The test is represented apparently only by the thin inner layer, which is 

 perfectly smooth. 



Dimensions. 



Specimen in British 

 Museum (No. C. 7967). 



Diameter of shell . . . .140 mm. 



Height of whorl at aperture about . . 60 „ 



Thickness at umbilical margin close to the aperture 



(perhaps somewhat affected by distortion) . 120 ,, 



Affinities. — I am not acquainted with any species with which S. clausus may be 

 compared. 



Remarks. — The completely closed umbilicus is the distinguishing mark of the 

 present species, and, so far as my observation carries me, this is uncommon among 

 the Nautiloids, the tendency in this group being to leave the inner whorls more or 

 less exposed even in those species which approximate most closely to the recent 

 Nantilus in their general form, which on the whole is the case with the Soleno- 

 cheilidae. 



Unacquaintance with the siphuncle throws some doubt on the generic position 



