232 



VITRINA HIBERNICA Taylor AND JEFFREYS' VARIETIES 

 OF VITRINA PELLUCIDA Muller. 



By LIONEL E. ADAMS, B.A. 



(Read before the Society, September 13th, Tgii). 



In the "Irish NaturaHst" for August, 1907, appeared a most inter- 

 esting account by Mr. J. W. Taylor of an addition to the Irish moUusca, 

 viz., Vitrina elongata Drap. (since altered to V. Jiiberiiica Taylor), 

 which had recently been discovered by Mr. P. H.Grierson in co. Louth. 

 It is just possible that conchologists will be interested in the con- 

 fusion that there has been with regard to the British Vitrina, and its 

 alleged varieties, one of which bears such a remarkable likeness to 

 V. Jiibernica that one might almost imagine that Jeffreys had a speci- 

 men of the Irish form before him when he wrote the description of 

 V. elongata. 



Mr. Grierson very kindly sent me three living specimens, which I 

 kept side by side with some V. pellucida for comparison. The differ- 

 ence between the two species is very marked, and Mr. Taylor's 

 description and remarks on them are very accurate ; however, I have 

 noticed two further points of difference, which I believe to be constant. 

 I. — \\\ pellucida the rim of the respiratory orifice is coloured with 

 black pigment, especially above, and this coloration is the 

 darkest occurring in the animal, while in hibernica the rim is 

 colourless and is the lightest portion of the animal. 

 2. — The spatuliform lobe of the mantle, which extends over the 

 nucleus of the shell in hibernica, is marked with the darkest 

 coloration to be found on the animal, while the same region in 

 pellucida is perfectly colourless. 

 When first I saw a shell of hibernica it immediately suggested the 

 elusive form of V. pellucida, named by Jeffreys var. depressiuscula, a 

 satisfactory example of which I have never seen. I quote here what 

 Jeffreys says on the subject in his " British Conchology," vol. i, 



P- 157 : — 



" Var. I, depressiuscula. — Shell rather oval and flatter on both sides : 

 spire scarcely raised above the level of the last whorl. V. drap- 

 arnaldi and V. depressa Jeffr. in Linn. Trans, xvi., pp. 326, 



327 Var. I, neighbourhood of Swansea and 



Plymouth (J.G.J.). It approaches very near to V. major of the 

 elder Ferussac and V. draparnaldi of Cuvier, with which I at 

 one time considered it to be identical." 



