188 GASTROPODA. [Pectinibranchia. 



2. Litorina mauritiana, Lamarck, 1822. Plate 38, fig. 28. 



Pfmxiiiiit'lfii iiiiiin-iliniKi. Lam., A.s.V., vii. 51. Lifurinn mauritiana. Lam., 

 P.L.S. N.S.W., ix. !J42; Man. Conch. (1). ix, 247, il. 44, f. 71-73. 75; 

 Pritchard and Gatliff, P.R.S. Vic., xiv (n.s. ). 90. L. unifasciatn, Gray, 

 King's "Survey of Australia," ii, App., 483. L. diemenensis, Q. & G., 

 Voy. Astrol., ii, 479, pi. 33, f. 8-11. L. ncutu, Menke, Moll. Nov. Holl., 

 9, No. 24. L. coerulescens, Lam. : Hutton, M.N.Z.M., 79, not of Lamarck. 

 And a good many more synonyms. 



Shell small, ovate-conic, imperforate, moderately solid, very often 

 much eroded. Sculpture consisting of regular fine and shallow spiral 

 grooves, more distant below the suture and subobsolete on the base ; 

 crossed by irregular oblique growth-strife and folds. Colour : Apex 

 brown, the succeeding whorls with the upper half white, the lower 

 blue, the last whorl white with a peripheral blue band ; mouth and 

 columella brown. Spire acute, conical, about the same height as tin 

 aperture, outlines slightly convex. Protoconch acutely conical, of 3 

 smooth, brown, flat, and polished whorls. Whorls 7, first slowly, the 

 last very rapidly increasing, flatly convex, the last angled below the 

 periphery ; base flatly rounded. Suture not deep. Aperture oblique, 

 oval, angled above. Peristom.e discontinuous, sharp. Outer lip with 

 a narrow yellowish margin inside. Columrlla oblique, arcuate, broad, 

 and flatly excavated, a very narrow groove on the outside ; parietal 

 wall with a thin white callus. Opcrcuhim normal. 



Diameter, 6 mm. ; height, 9-5 mm. Diameter, 6-5 mm. ; height, 

 12 mm. : angle of spire, 43. 



Dentition. Hutton, T.N.Z.I., xiv, 164. pi. 7, f. E. 

 Type in the Mus. Hist. Nat., Geneva. 



Hob. Common on rocks at and above high-water mark through- 

 out New Zealand and at the Chatham Islands ; Lord Howe Island, 

 Tasmania, Australia, Mauritius, Ceylon, Nicobars, Malay Archipelago. 



Genus 2. L^VILITOKINA, Pf offer, 1886. 



Lcevilitorina, Pfeffer, Jahrbuch Hamburg. Wissensch. Anst. iii, 1886, 81. 

 Type : Hydrobia culiginosa, Gould. 



A genus distinguished from Litorina by the niultidenticulate outer 

 marginal teeth of the radula. 



Shell chitinous, scarcely chalky, fragile, rimate. Per iconic thin, 

 sharp, the extremities united by a thin callus. Efiidcrnn's smooth. 



. Antarctic Sea. 



KEY TO SPECIKS. 



A. Shell turbinatc. 



a. Last whorl with two spiral bands. .. .. .. bifasciaia. 



an. Without spiral bands. 



b. Spire slightly higher than the aperture .. .. caliginosa. 



bb. Spire a little lower than the aperture . . . . antipodum. 



B. Shell subglobose, last whorl very large .. .. .. Hamiltoni 



