446 Mr. G. C. Crick on some 



about three fifths of the width of the side from the edge of 

 the umbilicus, that becomes obsolete on the anterior part of 

 the body-chamber ; umbilical zone well defined, rather 

 narrow, nearly perpendicular to the plane of symmetry of the 

 shell. Body-chamber occupying the whole of the last whorl ; 

 aperture not seen, but (judging by the growth-lines of the 

 test) the peristome probably with a prominent lateral crest and 

 a deep and rather narrow hyponomic sinus. Chambers 

 rather shallow ; suture-line as in fig. 1 1. Test nearly smooth, 



Fig. 11. 



Glyphioceras cordatum. — Suture-line drawn from the last septum of the 

 type specimeu in the collection of Dr. A. H. Foord, F.G.S. Carbon- 

 iferous Limestone : Little Island, Cork, Ireland. Natural size. 



apparently with only growth-lines which have a nearly radial 

 direction on the inner portion of the lateral area and turn 

 somewhat abruptly backward on the outer portion so as to 

 form a deep and moderately wide hyponomic sinus on the 

 periphery ; internal cast nearly smooth. 



Dimensions. 



A-B. C-D. 



Diameter of shell 116-5 mm. (100) 109-5 mm. (100) 



Width of umbilicus (at su- 

 ture of shell) 26 „ (22-3) 24-5 „ (22-3) 



Width of umbilicus (at its 



margin) 28-5 „ (24-4) 26 „ (237) 



Height of outer whorl about5L5 „ (44'2) about 48-5 „ (44-2) 



Ditto above preceding whorl about27-5 „ (236) about 25 „ (22-8) 



Thickness of outer whorl . . 56 „ (48) 55-5 „ (50'6) 



Remarks. I have seen only two examples of this species. 

 They are both from Little Island, Cork, and in the collection 

 of Dr. A. H. Foord, of Dublin. As is usual with specimens 

 from this locality, both are distorted, the one (the dimensions 

 of which are given above) only slightly, but the other 

 so much that its measurements are not given, since they 

 would be misleading. There cannot, however, be any doubt 

 as to the specific identity of the specimens. 



The trivial name has been suggested by the form of the 

 aperture of the shell. 



Affinities and Differences. This species is evidently closely 



