68 



GASTROPODA. [Aspidobranchia. 



Subsp. subtilis, Suter, 1907. Plate 5, fig. 12. 



Acmaa dwdala, subsp. subtilis, Suter, P. Mai. S., vii, 1907, 324, pi. 27, f. 33. 



This subspecies has the same microscopic sculpture as the species, 

 but it is more transparent, more fragile, smaller, whitish, ornamented 

 with fine brown radiate lines. Interior whitish, showing all the brown 

 lines ; central area slightly greenish, polished, but indistinctly circum- 

 scribed. 



Length, 2-5 mm. ; breadth, 1-5 mm. ; height, 0-05 mm. (type). 

 Length, 6-5 mm. ; breadth, -4-5 mm. ; height, 1-75 mm. (Taumaki 

 specimen). 



Dentition unknown. 



Type in my collection. 



Hob. Between Little Barrier Island and Tiri Tiri Island, in 20 

 fathoms, type (R. H. Shakespear) ; Taumaki Island, in 10 fathoms 

 (Captain Bollons) ; Shag Point ; Cape Saimders (Iredale). 



8. Acmaea fragilis, Chemnitz, 1790. Plate 7, fig. 2. 



Patella fragilis, Cuemn., Conch. C.,b., xi, f. 1921. Patelloidea fragilis, Q. & G., 

 Voy. Astrol., Zool., iii, 351, pi. 71, f. 28-30. Acmtei fragilis, Q. & G., 

 Man. Conch. (1), xiii, 59, pi. 37, f. 14. 15. Patella ungvis-almte. Lesson, 

 Voy. Coq., Zool., ii, 420. Patella Solandri. Colenso, Tasm. Journ. Nat. 

 Sci., ii, 1844, 226, 250 ; T.N.Z.I., xiv, 168. .4. fragilis, Cheran., P. Mai 

 S., vii, 317. 



Shell ovate, flattened, membranaceous, pellucid, with concentric 

 bands of brown and greenish-white. The whole surface is sculptured 

 by exceedingly fine, close, subequidistant radiate strise, cut up into 

 minute oval nodules by growth-lines. Colour dark brown, lighter 

 near the apex, banded with narrow white or light-green concentric 

 lines. Apex anterior, submarginal, exactly in the middle line, sharply 

 pointed, and directed forward. Inside with an emerald ring around 

 the muscle-impression, margin sharp, with a 

 brown border ; central area showing the con- 

 centric bands of the dorsal part of the shell, 

 and having an elongated patch of light 

 emerald in the centre. 



Length, 15mm. ; breadth, 12mm. ; height, 



2 m * n> TEKTH OF RADULA. 



Dentition. The 2 central and 2 anterior 



inner lateral teeth are hamate, the outer posterior laterals small and 

 conical. 



Anatomy. M. A. Willcox, " Jenaer Zeitschrift," xxxii, 1898, 

 pp. 411-56, pi. 17-19. 



Dentition. Suter, P. Mai. S., vii, 318, pi. 27, f. 11. 



Type (?). 



Hob. Throughout New Zealand and at the Chatham Islands, 

 under stones between tide-marks. It is local in distribution. 



Remark. This is one of our most constant species. 



