510 



Transactions . 



in which an animal lives ; but for the sake of uniformity I have also re- 

 corded under the same heading the stations in which dead shells were obtained. 

 In all cases, therefore, where information is given under this head (except 

 where noted " Challenger " Expedition) it signifies that I have actually 

 seen specimens from the Kermadecs of the species in question. Under 

 the heading " Distribution " (as distinct from habitat) I give the places 

 where the species has been found. Where this heading is omitted it signifies 

 that the species is, so far as is known, endemic in the Kermadec Islands. 



Gastropoda. 



Scutellastra kermadecensis (Pilsbry). 



Patella kermadecensis Pilsbry, "Nautilus," vii, 109, 1894. 

 Recorded, Pilsbry, I.e. 



Radula. -Formula 31 212 13. Rhachidian tooth very small, not nearly 

 reaching to the ends of the laterals. 1st and 2nd laterals, together with the 

 rhachidian, placed anterior to the 3rd lateral and uncini, simple, obtuse ; 

 3rd lateral with 4 cusps, of which the inner one is smallest, the next is 

 largest. Uncini oblique, with 1 cusp. 



Shell solid, heavy, broadly oval, narrowed in front. Apex slightly in 

 front of the centre. Slopes straight in all directions. Margin coarsely 

 and irregularly dentate. Height 0-25 to 0-40 of length. Sculpture : Shell 

 with raised angular, irregular, radiating ridges, usually only evident at the 

 margin, the greater portion of the upper surface having the ridges obliterated 

 by a covering of shelly matter. Young shell with close irregular high ridges. 

 Colour : Upper surface yellowish, but in adult shells the shelly covering 

 usually pale greenish-white. Inner layer porcellaneous white, the muscle- 

 impression often partially or wholly yellow. Margin of interior showing 

 the yellow of the external layer. 



Measurements of various shells are here given in tabular form. 



Specimen. 



Weight. 



Length. 



Breadth. 



Height. 



Thickness 

 at Apex. 



Ratio Height 

 to Length 

 (L=100). 



Habitat. — Abundant living on rocks from just above low-water mark 

 down to 2m. or 3 m.. Sunday Island. The largest specimens have been 

 taken in less than 2 m. of water at low tide. This species lives on the 

 upper surface of the rocks, and the shells are almost invariably covered 

 with coralline and other algae, together with Siphonaria, Elminius, and 

 young examples of their own species, all likewise covered with algae. Also 

 found on Macauley Island, Curtis Island, and French Rock. 



Fossil. — Small shells occur in fragments of volcanic tuff found on the 

 south-east coast of Sunday Island. 



