78 THE NAUTILUS. 



Aperture oblique, rounded, about one-fourth of the circumference ex- 

 cised at the parietal wall by the preceding whorl ; peristome simple 

 and thin, the columellar margin a little dilated. Alt. 1.5, diam. 

 2.7 mm. 



Suimura, Awa, Shikoku. Types no. 83884 A. N. S. P., from no. 

 961 of Mr. Hirase's collection. 



This species is excessively similar to the common European P. 

 rupestris, type of the genus Pyramidula. In fact, if found in the 

 western Paljearctic area, it probably would not be separated more 

 than as a subspecies. However, the whorls are more tubular, espec- 

 ially the last one. The Chinese Pyr. orphana (Heude) is also 

 closely related, but comparison with a specimen received from Pere 

 Heude shows it to be perceptibly rougher and with the last whorl 

 more depressed. 



The species of the typical group of Pyramidula differ from those 

 of the more widely distributed section Gonyodiscus in wanting 

 regular rib-strise. This is more constant than tiie degree of eleva- 

 tion, which varies widely in both groups. Some large forms, such 

 as Pyr. solitaria, also want the ribbed sculpture. It has elsewhere 

 been shown that the teeth and jaw of P. rupestris are like those of the 

 ordinary discoidal species; so that Dr. von MoellendorfF's hope that 

 it will prove generically distinct does not seem likely to be realized. 



Macrochlamys kagaensis Pils. & Hir., n. sp. 



Shell very narrowly umbilicate, globose-depressed, thin, greenish- 

 yellow. Surface very glossy and smooth, marked with faint growth- 

 wrinkles, the inner whorl densely and finely engraved with spiral 

 stria3, which are obsolete or nearly so on the last whorl. Whorls 

 4^, rather rapidly increasing, the last about double the width of the 

 preceding, rounded peripherally, convex beneath, impressed at the 

 axis. Suture shallows edged by a fine white line. Aperture slightly 

 oblique, wide lunate, the peristome thin and simple, slightly dilated 

 at the axial insertion. Alt. 9.5, diam. 15 mm. 



Hakusan, Kaga. Types no. 83881 A. N. S. P., from no. 974 of 

 Mr. Hirase's collection. 



A fine large species, allied to M. dnicis Pils., but much more 

 globose. M. perfragilis Pils., from Oshima, is very similar in form, 

 but has an even smaller umbilicus and more oblique aperture, be- 

 sides wanting the incised, clear-cut spirals on the inner whorls. 



