AIPOCERAS ? HAINESIANUM. 131 



of this sijecies, as was the case with Solenocheihts ? Jnbpriiieits, and its reference to 

 that genus may possibly prove to be erroneous. 



It is interesting to note among these very ancient Cephalopods of the Irish 

 Carboniferous seas the varying plans of whorl structure exemplified in their she-lls-. 

 The present species adds another to this category, and demonstrates once more the 

 richness of the marine fauna in this extreme western extension of the European 

 Carboniferous rocks. 



Besides the specimen here figured, there is one, less perfect, in the JMuseur.i 

 of Science and Art, Dublin, from the same locality. Both have been recently 

 collected. 



Locality. — Little Island, near Cork. 



Genus Atpoceras (see ante, p. lid). 

 AirocEEAS? Hainesianum, sp. nov. Plate XXXV, figs. 2 a, h. 



Description. — Shell composed of about one and a half to two very rapidly 

 enlarging incontiguous volutions. Both the dorsal and ventral areas are consider- 

 ably flattened through rock pressure, the crushing having come in a direction 

 oblique to the longitudinal axis of the shell. The cross-section is transversely 

 oval, the ratio of the two diameters being as 10 : 14 in the younger part of 

 the shell, where it has been less affected by distortion. The periphery is broadly 

 expanded ; normally it probably presented a broad, low arch when seen in profile. 

 The sides are narrowly rounded, and merge into the broad dorsal area, which is 

 slightly convex in the median zone, a faint ridge bounding this central area on 

 either side. The outline of the aperture is imperfect, only interrupted portions of 

 it remaining. No trace of a sinus is seen in the peripheral area, but dorsally it 

 appears to have had a broad and shallow sinus (fig. 2 h). 



The whole of the septate region of the shell is filled with crystalline calcite, 

 which has destroyed every trace of the septa and siphuncle. The surface of the 

 shell is perfectly smooth. 



Remarhs. — My attention was originally drawn to this species by my friend Mr. 

 Joseph AVright, F.G.S., of Belfast, to whose collection it now belongs, and who 

 kindly lent it to me foi* examination. It was formerly in the collection of Dr. 

 Haines, of Cork, whose gatherings in the neighbourhood of that city supplied some 

 of the material used by M'Coy in his ' Synopsis.' The specimen described is unique. 



Affinities. — The evolute condition of the whorls in this species has suggested 

 the view of its affinities expressed in the doubtful reference to Aipoceras. 



This uncertainty is caused by the fact that the whorls in the individual here 



