new or little-known G-oniatites/row Ireland. 



435 



and making an obtuse angle with the sides. Body-chamber 

 occupying rather more than an entire whorl ; aperture not 

 seen, but peristome (judging by the ornaments of the test) 

 probably nearly straight on the lateral area and with a mode- 

 rately wide and deep hyponomic sinus. Chambers (? depth) ; 

 suture-line not seen. Test ornamented with feeble riblets 



Fig. 3. 



Pericyclus roiuliformis. — Lateral view of the type specimen, showing 

 ornaments and well-marked constrictions of test. Carboniferous Lime- 

 stone : St. Doulagh s, Co. Dublin, Ireland. Drawn from an example 

 in the collection of Dr. A. H. Foord, F.G.S. About three fifths 

 natural size. 



crossing the whorl obliquely backward as far as the margin of 

 the periphery, and then passing abruptly backward, becoming 

 somewhat coarser and more prominent, and forming on the 

 periphery a moderately wide and deep hyponomic sinus ; the 

 outer whorl with seven or eight constrictions extending from 

 the margin of the umbilicus and having a similar direction to 

 the ornaments of the test, these constrictions being faintly 

 indicated on the surface of the test, but well marked on 

 internal casts. 



Diameter of shell 81 



Width of umbilicus (at 



suture of shell) 24 



Width of umbilicus (at 



its margin) 29 



Height of outer whorl... 325 

 Ditto above preceding 



whorl 22 



Thickness of outer 



whorl 32 



Dimensions. 



(i.) (ii.) 



mm. (10l>) 78 mm. (100) 



(29-6) 23-5 



(35-8) 295 



(40-1) 28 



(27-1) 19* 



(395) 30* 



(301) 



(37-8) 

 (35-8) 



(24-3) 



(38-4) 



(iii.) 

 42 mm. (100) 



16 mm. (38-0) 



17 „ (40-4) 



20 mm. (47-' 



(iv.) 

 735 mm. (100) 



25 „ (34'0) 



(42-1) 

 (37-4) 



(29-9) 



(43-5) 



27-5 



22 



32 



* Approximately. 



