l86 JOURNAL OK C0NC110I,o(.;y, VOI,. 1 3, NO. 6, Al'KIl,, 19II. 



var. acicula Brus., Journ. of Couch., 1893, vol. vii., p. 259. — 

 Scilly Islands, 4of. ; Achil Island. A very elegant form. 



var. nana Jeffr.— Scilly Islands (}3urkill and J.T.M.) ; Land's 

 End, Falmouth, Eddystone, Torbay, Freshwater West, Aberdovey, 

 Skegness, Killala Bay, Biindoran, lona, and Loch Boisdale. Not 

 C. tubercuhiris var. nafia of Searles \V^ood, which is C. concatenata. 

 This variety is characterised by its dwarf size and spindled shape, the 

 last whorl being contracted and narrower than the preceding one, 

 although spindle-shaped examples are found of all sizes. It is 

 generally an eighth-of-an-inch long, but my smallest are only half 

 that length, and the width is of every degree. 'J'his cannot be the 

 male, as queried by Jeffreys, for though widely diffused it does not 

 occur everywhere with the type, while in some instances it forms the 

 majority ; nor have I ever taken a living specimen with the type 

 from seaweeds or ascidians ; probably it has a distinct habitat. British 

 examples embrace a form intermediate in size between this and the 

 type, which is C. minima Brus., and, according to 'Weinkauff, C. neg- 

 lecta C. B. Adams. 



var. clarkii Jeffr. — Sark, Scilly, and Torbay. This variety is 

 very rare. A similar form (C hilineata Homes) is regarded by 

 Continental writers as a distinct species, presumably because their 

 specimens are found in colonies like other species, that they resemble 

 one another, and are all of a definite shape — short, stout, and 

 spindle-shaped, like a large var. nana, whereas British examples are 

 variable in form, and are met with rarely and singly ; I have not 

 seen two alike. Jeffreys writes of this variety : — " I must still retain 

 my own opinion that C. clarkii, alias bilineata or coppolce, is merely 

 a monstrous or irregular form of C. iubenularis. One of my speci- 

 mens, which has only two rows of tubercles on the lower whorls, 

 has three rows on two of the upper ones."* Gwyn Jeffreys appears 

 to me to have erred in supposing that because var. clarkii and C. 

 bilineata have two rows of tubercles, they must be identical. But 

 the tubercles of the two forms are not quite the same, and I have 

 previously mentioned an analagous form of Triforis perversa, Pro- 

 fessor Sars has recorded another of Cerithium inctiila, and still 

 another will be found in my notes on the iiext species. Probably 

 this aberrant form will ultimately be met with throughout the 

 genus, as I have a two-rowed specimen from the Algerian coast 

 of C. horrida Jeffr., which is a treble-rowed species. An enlarged 

 figure of var. clarkii will be found in " British MoUusca " (pi. ciii., 

 fig. 6) ; but like Sowerby's figure, except that it has two rows of 

 tubercles, it is otherwise unlike. The Rev. R. Boog Watson, writing 



1 Moll. ' Lightning' and 'Porcupine,' Pioc. Zool. Soc, 1085, p. 59. 



