132 Transactions. — Zoology. 



The radida (fig. 29) wants no explanation. The formula 

 is 26 — 1 — 26, with five distinct lateral teeth. 



I am still of opinion that 0. dimidiata belongs to the genus 

 Vitrinoidea, Semper, but I think it to be safer to retain the 

 generic name proposed by Professor Hutton until I have been 

 able to compare dentition and genital organs of our mollusc 

 with those of a Vitrinoidea from the Philippine Islands. But 

 the animal perfectly agrees with Semper's diagnosis of the 

 genus ; and there is one important fact which should be taken 

 into consideration : 0. dimidiata, when resting, brings its tail 

 forwards beside the body and head, a position I have never 

 seen taken up by any other mollusc. The figure of Vitrinoidea 

 albajensis given by Semper (Philippiuen, vol. iiii., Taf. viii., 

 fig. 2) shows a very similar position of the animal, and it seems 

 that Semper has also been struck by its peculiarity. The 

 figures of the teeth given by Semper are quite insufficient for 

 comparison. 



New SrEciES and Varieties. 

 1. Lagochilus fasciatum, n. sp. Plate XIX., figs. 30, 31. 



Shell small, turbinate, subperf orated, rufous, not shining, 

 rather thin, with close membranaceous, white, slightly sinuated 

 radiate plaits, about 11 or 12 per millimetre. They are crossed 

 by numerous distinct spiral striae. Spire conical, apex rather 

 blunt, smooth. Whorls 6, rounded, the first five slowly and 

 regularly increasing, the last rapidly growing in size. Peri- 

 phery rounded. There is a distinct horny band below the 

 periphery on the last whorl, as is sometimes seen also in 

 L. pallidum, Hutt. Suture impressed. The notch in the 

 peristome is slight, but quite evident at the point where the 

 upper margin meets the whorl. Aperture almost circular, 

 diagonal ; peristome simple, straight, strengthened inside by 

 a callous ring, the callosity extending over the body-whorl 

 between the convergent margins. Umbilicus very narrow, 

 previous, partly covered. Base rounded. 



Operculum not seen. 



Animal unknown. 



Diameter, 2mm. ; height, 2|^mm. 



Hah. Near Manaia, Waimate Plains, North Island, where 

 it was collected by Mr. E. Murdoch, of Wanganui. 



Note. — This species is near L. lied ley i, mihi, but may be 

 distinguished from it by the more elevated spire, the less 

 rounded whorls, the more numerous and equidistant plaits, 

 the very distinct spiral striation, and the horny band on the 

 last whorl. 



It is smaller than L. cytora, the spiral striae are much 

 closer, and in the latter the radiate plaits are provided with a 

 hair at the point where they cross the spiral striae. 



