288 PEOCEEDINGS OF THE MAlACOLOGICAl SOCIETY, 



broad, -with, a small rounded mesocone, tlie lateral cusps are minute. 

 The admedians (Nos. 1-10) have a short, broad inner cusp, with 

 short rounded cone, and a small outer cusp. In the succeeding laterals 

 (Nos. 11-16), the inner cusp is strong and broad, becoming (No. 16) 

 as long as the basal plate ; the outer cusp, though larger than in the 

 preceding ones, is still small. The marginals that follow (Nos. 17-32) 

 are tricuspid, with broad, short basal plate, the mesodont at first 

 flanked by a narrow, sharp endodont, and at a wider interval by 

 a small ectodont, gradually the endodont and mesodont coalesce, till 

 they finally form a single bifid denticle, with a small separate 

 ectodont. The last tooth of the series (No. 33) is minute, quadrate, 

 with a single small denticle. 



Reproductive organs (Fig. V). There is a long vestibule, the penis 

 is stout, broad, somewhat enlarged below the middle, constricted 

 above it, the distal end is flatly convex, the retractor muscle is 

 inserted at the anterior side of the distal portion, whilst on the 

 posterior end the vas deferens enters. A rather long distance from 

 the juncture of the penis with the vestibule, on the opposite side, the 

 long, subcylindrical receptaculum seminis arises ; this tapers off at its 

 extremity and forms a rather long, filiform caecum, slightly globular 

 at its end. The most interesting feature in these reproductive organs 

 is the fan- shaped, radially grooved appendiculum just opposite the 

 receptaculum seminis. In no other genus of New Zealand land 

 mollusca have I come aci'oss this interesting organ, although it is 

 known to occur in some Australian forms ; in these, however, it is of 

 a different shape, forming only a long, cylindrical sac. I have not 

 had an opportunity of dissecting the two other species of Pyrrha, and 

 am therefore unable to say whether the appendiculum is a constant 

 character of the subgenus. Since, however, in their shells and their 

 dentition the three species closely resemble one another, it is but fair 

 to presume that a similar appendiculum is present in all. 



4. Plammtjiina (Phacijssa) eulminata, Hutton, var. costata, n.var. 

 PI. XY, Pigs. 8 & 9. 



This variety differs from the type in its somewhat larger size, in 

 being costate, and in having mostly a different colour pattern. The 

 protoconch is microscopically radiately striate, the other whorls have 

 subequidistant low riblets, 4 to 5 per mm., between them are minute 

 lines of growth, which are decussated by spiral striae. The species, 

 which is only finely striate, is also microscopically decussate, a feature 

 not mentioned by Hutton. Of the six specimens (all of them more 

 or less damaged) only one shows the reddish-brown longitudinal 

 zigzag bands, the others having only broad, oblique streaks of the same 

 colour. The number of whorls is the same in both. Diam. maj. 12, 

 min. 1 1 mm. ; alt. 7 mm. 



^ff3.— Pesolution Island. I owe the specimens to the kindness of 

 Mr. R. Henry, caretaker of this reserve for the New Zealand fauna. 



Type in my collection. 



