546 Transactions. 



Siphonaria raoulensis n. sp. Figs. 40 and 40a. 



Recorded, Suter, Trans. N.Z. Inst., 39, 265 (S. diemenensis). 



Description oj Type Specimen. — Shell ovate-elliptical, conoidal, height 

 0-39 of length. Right side straight in centre, then rather sharply turning 

 to either end. Apex a little behind the centre, directed backwards and to 

 the left. Anterior slope slightly arched, posterior nearly straight. Margin 

 fairly regular and crenulated, chiefly on the right side. Siphonal groove 

 not prominent. Sculpture : There are about 40 rounded smooth and 

 polished radiating ribs. These are irregular in size, the larger ones being 

 chiefly on the posterior slope, while there are 2 prominent ones on the 

 siphonal groove. Colour : Bluish, darker towards the centre, the ribs 

 nearly white, especially near the margin. Interior light-bluish, the margin 

 nearly black, with white transverse bands opposite the ribs. At the 

 siphonal groove 2 white bands extend about half-way towards the apex. 



Length, 18 mm. Breadth, 12-8 mm. Height, 7 mm. 



Variations from Type. — The ribs vary somewhat in prominence, and the 

 general shape of the shell is liable to variation, as will be seen by the follow- 

 ing measurements : (a.) Length, 19-6 mm. ; breadth, 15-6 mm. ; height, 

 6-4 mm. ; ratio height to length (L. = 100), 0-31. (b.) Length, 19-8 mm. ; 

 breadth, 14-5 mm. ; height, 7 mm. ; ratio height to length, 0-28. (c.) Length, 

 17 mm. ; breadth, 13 mm. ; height, 7 mm. ; ratio height to length, 0-24. 

 The colour varies somewhat. The interior is sometimes nearly white or 

 yellowish, with a black -banded margin. The apex is occasionally eroded 

 and whitish. Most of my specimens were collected on rocks adjoining 

 sandy beaches, and show the effects of sand-rubbing in their highly polished 

 surfaces. 



Habitat. — Living on rocks between tide-marks, Sunday Island ; plentiful 

 in places. 



Siphonaria cheesemani n. sp. Figs. 41 and 41a. 



Description of Type Specimen. — Shell elliptical, slightly narrowed in 

 front, very depressed, height 0-21 of length, slopes nearly straight. Margin 

 deeply incised, the principal ribs projecting to a distance equal to their 

 width, slightly crenulated between the projecting ribs. Siphonal groove a 

 double rib, but not more prominent or projecting further than the other 

 large ribs. Sculpture : There are 13 high rounded radiating ridges, each 

 projecting beyond the margin. The anterior ridges slightly smaller than 

 the posterior. Ridges irregularly spaced, the largest interstice being behind 

 the siphonal groove, the second-largest immediately posteriorly to this. 

 Between the principal ribs are smaller riblets, chiefly noticeable on the right 

 side. The whole upper surface covered with crustaceous algae, apex eroded. 

 Colour : Interior nearly black, with a central white spot. Margin darker, 

 with white bands opposite the ribs and riblets. 



Length, 17-3 mm. Breadth between parallels touching the ribs, 13-5 mm. 

 Height, 3-7 mm. 



Variations from Type. — There being no adult specimens collected that 

 were not covered with algae, I am obliged to add the following particulars 

 from a smaller beach specimen : Apex situated behind and to the left of 

 the centre and directed away from the centre. Between the principal ribs 

 are fine close riblets. Concentric growth-lines show over the whole surface. 



The number of principal ribs varies in different shells, being usually 

 more than in the type, while the anterior ribs are frequently smaller and 

 more numerous than in the type. 



