146 Mr. G. B. Sowerby on the 



Cypraa, and on the other to Bulla, to which it seems to be connected 

 by the Bullm, Kaucum and cylindrica: this observation must, however, 

 be regarded as suggested by the general similarity in form of the British 

 Bulla patula, which I have here united to Ovulum, with the tv^o BuUcb 

 above named. 



In their general form the Ovula are more or less ovate or oblong; most 

 of the species are rather ventricose, a few are, however, nearly cylin- 

 drical: the spire is always hidden, its volutions being horizontal and not 

 descending as they increase, but always preserving the same plane : the 

 aperture is longitudinal, of the whole length of the shell, narrow at its 

 upper part, and more expanded towards the base : both the upper and 

 lower extremities are more or less notched, and each produced into a 

 longer or shorter canal : the inner or columellar lip is smooth without 

 teeth or crenulation ; a fold or pliciform tooth is, however, observable in 

 several species both at the upper and lower ends of this lip: the outer 

 lip is very seldom thin and sharp-edged ; it is generally thickened and 

 involute, frequently quite smooth, sometimes crenulated or denticulated. 

 In their young state the outer lip is thin and sharp-edged, and the out- 

 side is not covered with the shining enamel-like shelly coat. 



Since the pubUcation of Lamarck's Hist. Nat. des Anim. sans vert 

 (when only two were known), there have been considerable additions to 

 the number of fossil species, several small species having occurred in the 

 crag, in the calcaire grossier and in the contemporaneous formations, 

 near Bordeaux, in Touraine, at Piacenza, and in Britain:* I believe the 

 fossil Ovula have not occurred in any bed below the London clay. 

 '^''^ had prepared the above observations on the genus Ovulum, when 

 I was favoured by the Rev. Dr. Goodall with the following extract from 

 the Zoological part of the Vojrage de Freycinet, by M. M. Quoy et 

 Gaimard, which proves the correctness of my suggestion relative to the 

 animal of Ovulum, I am not, however, induced to degrade it from the 

 rank of a genus, because I think there ire sufficient distinguishing cha- 

 raofers. -^^ «K>i)f9« xf- 



♦ A large fossil shell having the form of Cyproea Mus, has been discovered 

 in Holland, and referred to this genus by M. Duclos, under the specific name 

 of O. tuberculosa; this shell is, however, more properly arranged with the 



Cijpraeoe. 



