236 



NOTE ON TROCHUS PENNANTI Philippi. 



By J. K. LE B. TOMLIN, M.A. 



(Read before the Society, April 6th, 1921). 



In several of the Channel Isles there is found commonly a Gibbula 

 which bears a close resemblance to the common uinbilicalis daCosta 

 {iimbilicata Mont.), but is usually more conical, differently coloured, 

 and in the adult state has no trace of an umbilicus. 



^ Forbes and Hanley refer to this form, but do not name it ; - Jefifreys 

 erroneously calls it var. agathensis Recluz — a well-known Mediter- 

 ranean form, which is always narrowly but deeply umbilicate. Jeffreys 

 als6 remarks (I.e., p. 314): — "it is the var. Iczta of the Rev. R. T. 

 Lowe." This is an equally bad shot ; I have Lowe's type series of 

 his ''var. lietus from Mogador in my collection, and find it to be a 

 distinctly perforate form as Lowe himself states. 



Norman corrected the Jeffreysian agathensis to var. sarniensis 

 Norm, in Mus. Norm., pt. iv, p. 20 (1888), but this name cannot be 

 considered valid as all the parts of the Museum Nornianianum are 

 "printed for private distribution." 



It is likewise the Gibbula u/nbilicatis da Costa var. iuiperforata 

 of Dautzenberg in his Liste Granville et Saint-Pair, p. 12. I have 

 however, recently in the British Museum come across the type speci- 

 men of Trochus peniiaiiti Phil., which Philippi ■* described as a British 

 species from the Hanley Collection, and which proves to be the 

 Channel form under discussion. 



It is, I think, a matter for congratulation that we can add to the 

 British list a name which commemorates so eminent a British 

 zoologist as Pennant. 



It now remains for the anatomists to determine whether or no this 

 form should resume the specific rank which Philippi so emphatically 

 claims for it. 



1 British Mollusca, II, p. 521. 



2 British Conchology, 111, p. 313. 



3 Proceedings of the Linnean Society, 1S60, p. 179. 



4 Syst. Conch. Cabinet, p. 224, pi. xxxiv, f. 10. 



