106 Mr. Jeffreys on British Mollusca. 



them have yet flowered. Yet I am convinced that in this plant 

 careful observation will clear up the matter. I may refer to the 

 peculiar glands which surround the female flowers, with which 

 solitary imperfect anthers might be easily confounded*. 



Parthenogenesis certainly does not occur in plants with evi- 

 dent sexual organs. 



Petersburg, Aug. 13, 1858. 



XV. — Further Gleanings in British Concholugy. 

 By J. GwYN Jeffreys, Esq., F.R.S. 



[Concluded from page 43.] 

 [With a Plate.] 

 G-asteropoda ProsobrancMata. 

 Chiton gracilis, n. s. PI. III. fig. 9 a, h. 

 Testa elongato-oblonga, convexa, colore vario ; valvulis clypeiformi- 

 bus; rostris prominentibus, mucronibus subacutis ; areis rostralibus 

 lineatis, fere seque latis ; grauulis numerosis, inter Ch. fascicular em 

 et Ch. discrepantem media ; fasciculis brevibus, 18 ut in congeneri- 

 bus et 1 ad termini postremi medium dispositis ; vitta marginali 

 lata, coriacea, setulis perbrevibus caducis sparsis obtecta ; margine 

 crinito ; long. 1, lat. \ unc. 



I detected several specimens of this new and interesting species, 

 mixed with Chiton fascicularis, among some shells of Mr. Damon 

 which bad been dredged in deep water at Weymouth ; and Mr. 

 Metcalfe also procured it, many years ago, in the same locality. 

 Mr. M'Andrew took the same species, in 1848, by dredging off 

 Milford Haven, and considered it to be C. discrepans. It, however, 

 differs from that species in its more elongated and arched form, the 

 granules being less numerous, the tufts less developed, and the mar- 

 gin much less hairy ; from C. fascicularis it may be known by the 

 same distinctive marks, except that the granules are less numerous 

 in that species ; and from both of those species in the marginal band 

 being coriaceous, as in C. marmoreus, and in having an additional 

 tuft at the posterior extremity. In order to further elucidate the 

 distinction of these three species (viz. C. fascicularis, discrepans, and 

 (gracilis), I have given, in PI. III. figs. 9 b, 10 & 1 1, representations 

 of their lingual ribands or tongues, by which it will be seen that they 

 all essentially differ from each other. These species, as well as C. 

 Hanleyi, belong to the genus Acanthochcetes of Leach. C. gracilis 

 is more probably the C. discrepans of Brown than the species which 

 the late Mr. G. B. Sowerby named " crinitus\'' but as the former 



* The author does not apj)ear to be aware that the characters of the 

 male flowers of Cculeboyyne are well known. M. Baillon has proposed the 

 same imsatisfactory explanation of this case. — A. 11. 





