Mr. Jeffreys on British Mollusca. 497 



correspondents furnishing any intermediate gradation of size between 

 half-grown specimens and the fry. To Mr. Clark I therefore acknow- 

 ledge myself indebted for the suggestion which has led to the correc- 

 tion of this error. I had intended to do this in my next paper. 



Page 408. Jporrha'is pes-carhonis. Mr. Barlee assured me that the 

 specimens of this now well-known species and of A. pes-pelecani^ from 

 a careful comparison of which he supplied me with the information 

 which I communicated as to the difference in the animals, were taken 

 toff ether ; so that the doubts raised by Mr. Clark fall to the ground. 

 These species differ as to the shell not merely in size (which Mr. 

 Clark supposes the only point of distinction), but also in the form of 

 the digitations of the outer lip in A. pes-carbonis (the posterior one 

 being generally produced beyond the tip of the spire), in the whorls 

 being more swollen, in the apex being more blunt, and in having a well- 

 defined but narrow umbilicus. I suspect it is the Chenopus desciscens 

 of Philippi (ii. 185. t. xxvii. f. 7), and not his C. Serresianus. One 

 of my specimens has five digitations, and exactly. agrees with the 

 figure of Philippi above quoted. 



Page 409. Rissoa pulcherrima, Cerithiopsis pulchelltty Buccinum 

 Humphrey sianum. Mr. Clark is of course at full liberty to entertain 

 and express his own opinion as to the validity of all or any of these 

 species ; but I do not believe that any other conchologist coincides 

 in it. 



Triton nodiferus. My belief that this is a British species is 

 founded on the fact that Mr. Lukis is a gentleman of unquestionable 

 veracity and accuracy ; and I see no more reason to doubt its being 

 indigenous than T. cutaceus or Murex erinaceus, 



Triton cutaceus. Mr. Clark's idea was quite new to me, and I 

 imagine it was equally so to your other readers, that it is the habit 

 of this or any analogous species to adhere to the bottom of a vessel ! 

 Another live and adult specimen has recently been taken in Guernsey, 

 a notice of which will appear in due time with other discoveries. 



Kellia lactea. It occurs in the same habitat, and even in the same 

 stones, as K. suborbicularis. I would recommend Mr. Clark to re- 

 consider his decision. 



Mytilus Galloprovincialis and M. ungulatus. I cannot dispute 

 the fact that Mr. Clark thinks differently from other naturalists ; but 

 I may remind him and your readers that the specimens from the 

 Channel Isles, upon which my remarks were founded, were taken in 

 the same locality and at the same season of the year — in fact, within 

 a space of 10 yards and 10 minutes from each other. " The animal 

 of the Mytili [doubtless] varies greatly," owing to the causes as- 

 signed by Mr. Clark, as well as to the circumstance that the genus 

 contains many species. 



Page 410. Jeffrey sia ? Gulsonce. Until the animal is known, the 

 generic position of this species can only be assigned on conchological 

 grounds ; and these grounds have been so fully discussed before in 

 the ' Annals,' that it is unnecessary to recapitulate them. The only 

 character it appears to have in common with Odostomia or Chem- 

 nitzia is that of being a turbinated Gasteropod. Mr. Clark ought 



Ann. ^ Mag, N. Hist. Ser. 3. Vol. iii. 32 



