332 Mr. J. G. Jeffreys on the recent species of Odostomia 



denticulated aperture, such as Pupa, Clausilia, &cc., but was sub- 

 sequently restricted, or rather transferred, by that author in his 

 ' Hist, of Brit. An.^ 1828, to a series of submarine shells with an 

 oval apei-ture and a single plait upon the columella.^^ 



The name was also included by Dr. Fleming, in his ' Philo- 

 sophy of Zoology,' (published in 1822,) among the marine Tur- 

 bonidce. 



In an ' Enumeration of Marine Shells ' found on the Devon- 

 shire coast, which was edited by Dr. Turton and published in 

 1829, the generic name of O^on^os/owflt was proposed by him for 

 these shells, the character being thus given : '^ Shell conic oval ; 

 pillar with a single tooth or fold towards the middle ; operculum 

 none. Includes Turbo unidentatus and others.''^ But this de- 

 scription as regards the absence of an operculum is obviously 

 incorrect. 



To show the extent of confusion which prevails in the syno- 

 nymy of this genus, I may remark that Herrmannsen in his 

 ' Index Generum Malacozoorum * gives no less than nineteen 

 synonyms for the genus Chemnitzia of D'Orbigny, which forms 

 a group of the present genus. 



Equal confusion seems to prevail as to the synonymy of the 

 British species. The Turbo unidentatus of Montagu is a very 

 different shell from the Turbo unidentatus of Turton and Odo- 

 stomia unidentata of Fleming ; and the shell described in Thorpe's 

 work as the last-named species is again very different from either 

 of the two former. Other specific errors have been occasioned 

 by authors taking their descriptions from imperfect specimens. 

 Having through the kind liberality of many authors on the sub- 

 ject of British Conchology, as well as the possession of the late 

 Dr. Turton's collection, had an opportunity of examining their 

 specimens, I am enabled to clear up most of these errors. 



It is in my opinion impossible, without doing considerable 

 violence to the established ideas of the system on which generic 

 differences are founded, to separate Chemnitzia or Eulimella from 

 this genus. The same character, viz. the shell forming a more 

 or less cylindrical cone, having the peristome incomplete retrally, 

 and leaving the upper part of the pillar exposed, belongs to all 

 the species ; and although the tooth or fold on the pillar is cha- 

 racteristic of the typical species, the case of O. indistincta, which 

 is scarcely distinguishable from its congener interstincta (the 

 latter being destitute of any tooth or fold), shows that this cha- 

 racter cannot be relied upon for generic distinction. Typical 

 specimens of Odostomia plicata are also closely allied in form as 

 well as in the glossy smoothness of their shells to O. acicula, 

 which would otherwise be a Eulimella. The Chemnitzia dense- 

 costata of Philippi, which is described by that author as having 



