72 GASTROPODA. [Aapidobranchia. 



12. Acmaea scapha, Suter, 1907. Plate 5, figs. 15, 15a. 



Acmcea scapha, Suter, P. Mai. 8., vii, 324, pi. 27, f. 34, 35. 



Shell very small, long and narrow, laterally compressed, sides 

 parallel. Nearly the whole surface of my specimens is eroded, but 

 near the margin traces of radiate fine riblets can be seen. Colour light 

 brown, with a few concentric bands of darker. Apex situate at about 

 the anterior fourth, rounded ; side slopes steep and straight, anterior 

 slope straight, posterior slope convex. Inside with the central area 

 dark brown, lighter under the apex, a narrow brown border on the 

 margin ; space between this and the spatula covered by a whitish 

 callus. 



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



Dentition unknown. 



Type in my collection. 



Hub. Dunedin, type (A. Hamilton) ; Blind Bay, Nelson. 



Remarks. This curiously shaped species resembles somewhat the 

 Californian species A. palacea, Gould, and A. depicta, Hinds. Whether 

 in this case the narrow elongated form is an adaptation to life on fronds 

 of seaweeds I am unable to say, but it seems very likely. 



13. Acmaea septiformis, Quoy and Gaimard, 1834. Plate 7, fig. 5. 



Patelloidea septiformis, Q. & G., Voy. Astrol.. Zool., iii, 1834, 362. pi. 71. 

 f. 43, 44. Acmcea septiformis, Q. & G., Man. Conch. (1), xiii, 55, pi. 37, 

 f. 93, 94. A. scabrilirata, Angas, P.Z.S., 1865, 154; Man. Conch. (1), 

 xiii, 56. A. Petterdi, T.-Woods, P. Roy. S. Tasm., 1876(1877). 155; 

 Man. Conch. (1), xiii, 54. A. septiformis, Q. & G.. P. Mai. S.. vii, 318 : 

 Verco, T.R.S. S.Aust., xxx, 215. 



Shell oval, conical to depressed, radiating riblets distinct or nearly 

 obsolete, sometimes tessellated with green and white. The sculpture 

 is very variable ; typically the shell is delicately radiately striated, 

 but specimens occur which have acute, distant, and slightly granulose 

 radiating riblets, whilst others show almost no trace of sculpture. 

 The colour is brown, tessellated with green or white, but uniformly 

 dark-brown examples are also met with. The apex is at about the 

 anterior fourth, but very often submarginal or even marginal ; it is 

 pointed forward, and obtuse. Inside blue or whitish, lineolate with 

 brown. In specimens from the Auckland Islands and Campbell 

 Island the whole of the interior is bluish-black, a lighter band around 

 the central area ; it is beautifully iridescent with dark blue, quite 

 an exception in this family. Margin sharp, usually with a brown 

 border, which is sometimes banded with yellowish. 



Length, 14 mm. ; breadth, 12 mm. ; height, 6 mm. Length, 

 15 mm. ; breadth, 11 mm. ; height, 7 mm. (from Auckland Islands). 

 Length, 16-5 mm. ; breadth, 12-5 mm. ; height, 4 mm. (from Chicken 

 Island). 



