igiS. pRAEGAR. — Irish Fossil Molliisks. 73 



case of their carriage over long distances. I question if they 

 are, as a group, more small-seeded than any other natural 

 group, or group selected at random, within the native flora. 

 But here I get beyond the bounds of the present notice ; I 

 shall hope to return to this portion of the evidence on a 

 future occasion. 



There remains, then, the " Edward Forbes theory," and 

 this Messrs. Kennard and Woodward adopt in the present 

 paper, as they have done on previous occasions, as best 

 accounting for the facts of the past and present nature and 

 distribution of the molluscan fauna ; this, of course, involves 

 the presence of the existing fauna in the country in pre- 

 Glacial times, and its survival through the Ice Age. They 

 refrain from expressing any opinion as to how this survival 

 was effected. As regards the post-Glacial liistory of the 

 molluscan fauna, they hnd, especialh-^ in the sand-dune 

 deposits, evidence of a climatic optimum in Neolithic times, 

 such as has been previously ]Dostulated locally from studies 

 of the marine mollusca and other groups, and which is 

 widely accepted in northern Europe. 



To one who, like myself, is not a special student of the 

 Mollusca, the study of the present paper is rendered difficult 

 by the nomenclature which is employed. It is true that as 

 regards this vexed question the authors claim to have 

 adopted a moderate middle course — they adhere to the 

 " modern school " as represented by Hyatt and Grabau, and 

 adopt Hannibal's definition of a species — " a number of 

 related individuals, having a similar genetic history and 

 possessing a tendency to evolve along strictly analogous 

 lines." They neither " lump " according to the " Jeffreysian 

 school " nor " split " according to the " French school," and 

 so far one has no cause for grumbling ; but the names which 

 they use for their species are in many cases vmfamiliar to 

 all but the few who follo\\- with avidity the search for the 

 oldest name — a search which results in the continual 

 changing of names. If a paper like the present is to be used 

 by any but the small coterie referred to, it must be intelli- 

 gible to the general worker at natural liistory ; and until 

 something approaching finality is reached, it is nmch better 

 to stick to a familiar nomenclature, even at the risk of being 



