46 ACM^A. 



with irregular obscure lighter olive-yellow streaks in the interstices. 

 Interior bluish-white ; border not distinctly defined, having indis- 

 tinct dark tesselations. Central area defined and obscurely clouded 

 with dark chestnut. Length 30, breadth 24?, alt. 14 mill. 



Hakodadi, Japan. 



A. dorsuosa Gld., Proc. Bost. Soc. N. H. vii, p. 162,1859. Otia, p. 

 115. — Watson, Challenger Gastrop. p. 29, t. 4, f. 1. 



This species, which I have figured and described from types, is evi- 

 dently allied to A. persona and pelta of the Californian coast, but is 

 quite distinct. The ribs are variable in number, 20 to 27 being de- 

 veloped ; they are obsolete in front. The periods of arrested growth 

 are strongly marked. It is likely that "Tectura digitalis" reported 

 from Hakodadi by Dunker (Ind. Moll. Mar. Jap. p. 154) is this 

 species. 



No other Japanese Acmcea is so strongly ribbed as this. 



Watson figures a slightly differing variety from Oosima. See pi. 

 9, figs. 15, 16. 



VI. Indo-Pacific, Australian and New Zealand Species. 



The Australian region is rich in forms oi Acmcea, but the number 

 of species is doubtless less than are herein admitted. The lack of 

 extensive suites has prevented me from working up the synonymy 

 as fully as I would desire. 



There are but few Polynesian Acmseas, and a still smaller number 

 are found in the Indian Ocean. 



The following species I have not seen : A. hiradiata Rv., rugosa 

 Q. & G., cingulata Hutton, conoidea Q. & G., petterdi T.-W., septi- 

 Jorniis Q. & G., laciniata Rv., cantliarus Rv., scabrilirata Ang., 

 fiammea Q. & G., subundulata Aug., pileopsls Q. & G., orbicularis 

 Q. & G., mixta Rv., elongata Q. & G., punctata Q. & G., squamosa 

 Q. &G. 



A. coNOiDALis Pease. PI. 33, figs. 93, 94, 95. 



Shell solid, thick, short-oval, elevated, straightly conical, the apex 

 erect, pointed, subcentral, slopes of the cone straight or the posterior 

 a little convex. Surface sculptured Avith numerous close, rather 

 fine radiating threads, alternately larger. Whitish or yellowish- 

 white. Edge thick, very finely crenulated. 



Inside yellowish, the central area opaque white. Basal side mar- 

 gins somewhat arched. Length 22, breadth 17, alt. 11 mill. 



Raratonga, Cook Is. ; Hervey Is. 



