196 



ON CHLORITIS HETEROMPHALUS, PILSBRY. 

 By Prof. Henry A. Pilsbry, Sc.D,, etc. 



Read 8th June, 1906. 

 In the Manual of Conchology, vol. vi, pi. li, figs. 60-62, a Chloritis 

 was figured which, by some oversight, was not described in the text, 

 though the name appeai-ed in the explanation of plates, p. 320. No 

 other reference to the shell has come to my knowledge, and the species 

 was apparently forgotten until Mr. G. K. Gude, in a recent letter, 

 directed my attention to it. A description is offered below, with new 

 figures, more correct in outline than those originally published. 



Shell planorboid, rather openly umbilicate, the umbilicus contained 

 about 6|^ times in the diameter of the shell ; yellowish-brown, with 

 a tinge of flesh -colour, paler and whitish around the umbilicus, and 

 with a faint pale band along the summit of the last whorl. Sculpture 

 of indistinct growth-lines, and faint, close, and very fine spiral strife, 

 more distinct below than above. Spire moderately concave. Whorls 

 5, convex, at first very slowly widening, then, at the later half of the 

 penultimate whorl, more rapidly so, the last whorl unusually wide, 

 rounded peripherally, its last fifth slowly descending to the aperture. 

 The aperture is very broadly crescentic, and quite oblique. The 

 peristome is well expanded, the basal margin narrowly reflexed. The 

 upper and outer margins are more arcuate than the basal, which is 

 dilated at its insertion. The parietal callus is thin and transparent. 

 The umbilicus is well-like, contracting slowly within. Alt. 12-7 mm. ; 

 greater diam. 26'5, lesser 21 -8 mm. 



Hab.—l^ew Guinea. Type No. 58,217 A.N.S.P., presented by 

 Dr. T. B. Wilson ; collector unknown. 



A much smaller specimen, with the lip partly broken, is with the 

 type. It would, if perfect, measure only about 19 mm., yet agrees so 

 closely with the type that I do not doubt that the tw^o are specifically 

 identical. 



This species evidently belongs to the group of C. circumdata, and is 

 nearest, I think, to C. Alaforemis, Tapp.-Can., which differs by having 

 a much more narrowly lunate aperture, and a coloration somewhat 

 different. There can be no doubt that the type of C. heteromphalus is 

 much faded, yet it certainly was never multifasciate, like Maforensis 

 or microniphalus. 



The upper part of the last two whorls, near the suture, is very 

 weakly plicate radially. The pale band along the upper convexity of 

 the last whorl is so faint as to be hardly noticeable unless closely 

 looked for. 



