TORNATELLINA. 165 



PEASE, Proc. Zool. Soc., 1864, p. 672 ; 1871, p. 4XS.Tornatel- 

 lina Iccvis PFEIFFER, Monogr. Hel. Viv., vi, p. 266. 



Garrett does not record serrata among the snails of the Fiji 

 or Marquesas groups in his catalogues of those faunas. He 

 states that it is "distributed throughout southeastern Poly- 

 nesia." Such indefinite data are often the record merely of 

 a general impression of the collector, and have but slight sci- 

 entific value. 



T. serrata may be recognized by its conic shape, very convex 

 whorls, strong columellar and parietal lamellae, and vertical 

 palatal laminae, which are serrate when fully developed. In 

 T. subcylindrica the palatal laminae and columellar lamellae 

 are lost in the adult stage, and the shell is more cylindric. 



Figures 1 and 2 represent a specimen of the original lot of 

 serrata, received from Pease. It is not mature, measuring 2.2 

 mm. long, 1.3 wide, with 4% whorls. The columella is nearly- 

 straight, solid, without a fold above, but it has a single strong, 

 horizontal median lamella. The parietal lamella appears 

 subtriangular in basal view, as usual in immature specimens. 

 There are two serrate laminae within the last whorl, one dor- 

 sal, the other near the aperture. 



Examples from Cook's (Hervey) Is., pi. 33, figs. 4, 5, differ 

 by having an obtuse fold above the subhorizontal columellar 

 lamella, the latter being superposed upon a strongly plicate 

 columella. The adult shells measure, length 3, diam. 1.7 mm. 

 (figs. 4, 5). Young shells down to 2.2 mm. long are similar to 

 fig. 5, except that the upper fold of the columella is a little 

 weaker in some shells. 



The Society Island shells (pi. 33, fig. 3) are like those from 

 Cook's Islands, the upper fold of the columella being well de- 

 veloped. 



Lamellina Icevis Pse. is, as Garrett has stated, merely ser- 

 rata with the palatal laminae smooth or nearly so. Each lam- 

 ina passes through a smooth stage before reaching its maxi- 

 mum size, and again in the process of being absorbed. One 

 of the original lot of Icevis collected in the Society Is. by Gar- 

 rett, and received from Pease, is figured, pi. 33, fig. 6. 



