74 yermetidjE. 



the TurritellidcB as proposed by Forbes and Hanley, or 

 adopting Gray's name of Ccecidce. The affinity of C cecum 

 to Vermetus is certainly very close, in respect not only 

 of the animal, but also of the shell and operculum. 



Genus CECUM * Fleming. PL I. f. 6. 



Body short. 



Shell free, forming a curved and small cylinder, having in 

 an early stage of growth a loose but regular coil of whorls, 

 which afterwards falls off, the truncated extremity being then 

 closed by a plug: operculum solid. 



Costa would not believe the strange metamorphosis 

 which the shell undergoes ; but it is constant in every 

 species. Such similitude in dissimilitude teaches us, as 

 it did Charles Lamb, 



" That harmonies may be in things unlike." 



From Professor Stimpson's account of C. pulchel- 

 lum it would seem that a fresh truncation takes place 

 during each of the last three stages of growth, when a 

 separate plug or septum is formed. This genus is evi- 

 dently allied to Omalaxis or Bifrontia, in the convolution 

 of the spire and form of the operculum. Our knowledge 

 of the animal is entirely derived from Mr. Clark's excel- 

 lent observations. Mr. Alder says, as to the tongue of 

 C. trachea, " the lateral spines, in two longitudinal rows, 

 are slender and very numerous, with a minute plate in 

 the centre/' The ' Proceedings of the Zoological So- 

 ciety of London ' for 1858 contain an elaborate mono- 

 graph on the recent Caddce by Dr. P. Carpenter. Fossil 

 species occur in the Eocene and Pliocene strata of this 

 country and Italy. 



* A blind gut. 



