436 



& Rack. Trans. Linn. Soc. vol. viii. p. 239 ; Turt. Conch. Diet, 

 p. 40 ; Br. Mar. Conch, p. 4. f. 5 ; Wood, Ind. Test. Ed. Hani, 

 p. 192. no. 14. f. 12. 



Ccecum glabrum, Flem. Enc. Edinb. pi. 204. f. 7, pi. 205. f. 8, 9 ; 

 Forbes & Hani. Br. Moll. vol. iii. p. 181. pi. 69. f . 5 ; H. & A. Ad. 

 Gen. vol. i. p. 356 ; Clark, Test. Mar. Br. p. 329 ; Searles Wood, 

 Crag Moll. p. 117. pi. 20. f. 6 ; M'Andr. Br. Ass. Rep. Moll. N.E. 

 Atl. 1856, p. 149 ; Jeffr. Mar. Test. Piedm. p. 30. [Non M'Andr. 

 Geogr. Distr. 1854 ; B.M. Cat. Shells Canar. p. 29.] 



Br ochina glabra, Gray, Syst. Distr. Moll. p. 101. 



Orthocera glabra, Flem. Br. An. p. 237. 



Odontidium levissimum, Cantr. Bull. Brux. vol. ix. p. 2, 1842. 



Brochus glaber, Brown, 111. Conch. Gr. Br. p. 125. no. 5. pi. 56. 

 f. 3. 



? + Brochus Icevis, Brown, loc. cit. no. 6. f. 6*. 



T. adol. = Brochus arcuatus, Brown, 111. Conch. Gr. Br. p. 125, 

 no. 7. pi. 56. f. 9 ; Forbes & Hani. Br. Moll. vol. iii. p. 182. 



T. jun. = ? Serpula incurvata, Walk. Test. Min. f. 11, 1787; Ad. 

 Micr. pi. 14. f. 7 ; Maton & Rack. Trans. Linn. Soc. vol. viii. p. 246; 

 Turt. Conch. Diet. p. 156 ; Dillw. Rec. Sh.vol.ii. p. 1071 ; Wood, 

 Ind. Test. ed. Hani. p. 192. no. 3. pi. 38. f. 3 m. 



Vermiculum incurvatum, Mont. Test. Br. p. 518. 



1 =Cornuoides minor, Brown, 111. Conch. Gr. Br. p. 125. no. 2. 

 pi. 56. f. 50 : " = Serpula recta, Walker, Flem." 



[? Non 1 Ccecum 1 incurvatum, S. Wood, Crag Moll. p. 117. pi. 20. 

 f. 7a, b, = 1 Serpida recta, S.Wood, Cat. 1842: ? = Ccecum mamil- 

 l a turn, jun.] 



The shell is described as snow-white by Hanley. This is true of 

 dead specimens ; but when fresh it is somewhat horny in texture, 

 and so pellucid, that the shape of the operculum within can easily be 

 seen through the shell by transmitted light. The English specimens 

 generally have the plug somewhat flattened, presenting not more 

 than a tbird of a sphere ; but many of the Mediterranean shells, 

 especially when young, are so inflated as closely to resemble the Ma- 

 zatlan species. 



I have carefully examined about thirty specimens with the oper- 

 cula in situ, of which part were dredged by Mr. M' Andrew in the 

 Mediterranean, part were most kindly placed at my disposal by Mr. 

 Clark. From several of these, after softening the animal in dilute 

 potash (till the viscera were clearly discernible through the trans- 

 parent shell), I removed the opercula, and subjected them to a rigid 

 scrutiny, by transmitted and reflected lights, under various achro- 

 matic powers up to \ in. I am not able to confirm all the observa- 

 tions recorded by Mr. Clark, and presume that some of them may 



* This may be a foreign species, as the aperture is said to be somewhat con- 

 tracted ; but as the protuberance is further said to be central, it is probably, as 

 Hanley supposes, a form of B. glabra. " D. imperforatum. Walker, Mont.," is 

 cited as a synonym : perhaps the author may have been misled by the figure in 

 Wood (r.o. 12), which corresponds with D. imperforatum, but is clearly intended 

 to represent D. glabrum. 



