GASTROPODA. 103 



1. Scutus ambiguus, Chemnitz, 1795. Plate 8, fig. 7. 



Patella ambigua, Chemn., Conch. Gab., xi, 178, 181, f. 1918. Scutus 

 ambiguus, Chemn. : Smith, Quart. Jouni. Conch., ii, 1879, 258, f. 1-3 ; 

 Mm. Conch. (1), xii, 289, pi. 40, f. 9-11. Scutus antipodes, Montfort, 

 Conch. Syst., ii, 1810, 58, 59. Parmophorus breviculus, Blainville, Bull. 

 Sci. Soc. Phil., 1817, 28. Scutus unyuis, L. : A. Adams, P.Z.S., 1851, 

 221 ; Hutton, M.N.Z.M., 106, not of Linna-us. Parmophorus auslralis, 

 Lamarck : Hutton, C.M.M., 43, not of Lam. 



Shell oblong, length about twice the breadth, depressed, sides 

 parallel, posterior end rounded, anterior end squarely truncated, 

 sinuated. Surface concentrically striated. Colour brown, in adult 

 large specimens often white, eroded. Apex low, at about the pos- 

 terior fourth. Inside white, sometimes bluish or greyish inside the 

 muscle-scar ; the latter is distinct, rugose. Margin callous, smooth, 

 rounded. 



Length, 54 mm. ; breadth, 28 mm. Length, 63 mm. ; breadth , 

 35 mm. (my largest specimen). 



Animal. Ration, T.N.Z.I., xiii, 203. 



Dentition. Ration, T.N.Z.I., xv, 127, pi. 15, f. I. 



Type (I}. 



Hob. North and South Islands of New Zealand, but more com- 

 mon in the North. 



Maori. Rori (fide Captain Bollons). 



Genus 5. PUNCTURELLA, Lowe, 1827. 



Puncturella, Lowe, Zool. Journ.. iii, 77, 78. Type: Patella noachina, L. 

 Cemoria, Leach (MS., 1819), Moll. Gr. Brit. (Gray's edit.), 1852, 213; 

 Ad., G.R.M., i, 450. SipJio, Brown, 111. Conch. Gr. Brit., 1827, pi. 36, 

 f. 14-16; not of Klein, Fabricius, Moerch. Puncturella, Man. Conch. 

 (1), xii, 202, 228. 



Animal with a tubular process, surrounded by papillae, passing 

 through the perforation, being formed by the mantle ; epipodial line 

 with a series of conical tentacles ; a cirrus on the dorsal part of the 

 foot. Jaws fibrous ; radula that of Emarginula. 



Shell small, conical, having a spirally recurved apex either per- 

 sistent or absorbed in the adult, the fissure either lanceolate or oval, 

 on the front slope or at the summit of the cone ; inside there is a 

 plate extending forward, forming a conduit to the fissure or a " deck ' : 

 over it. The spiral apex is inclined toward the right side, and 

 the fissure is also a trifle to the right of a median line, when visibly 

 excentric. The surface usually shows minute granules under a strong 

 magnification. 



This is mainly a deep-sea group, living in the northern and southern 

 cold seas. About thirty species are known. 



Fossil in the Tertiary of Italy. 



