320 RECORDS OF THE AUSTRALIAN MUSEUM. 



Animal. — As only dried material was obtainable, nothing but 

 the radula could be deciphered. 



Dentition — Fig. 29. 3 + 1+3. The rachidian is bluntly uni- 

 cusped, provided with a broad root; the first lateral has three 

 blunt cusps, the centre one broadest ; the second, has one cusp on 

 the distal attached end, and a long scythe-like blade as the proximal 

 end ; the third lateral is a simple scythe-like blade ; all three are 

 provided with long narrow roots. 



Type. — Fossarina varia, Hutton." 



The porcellaneous interior, and indeed the general texture of 

 the shell, are strikingly like Risella, so much so that I was 

 inclined to assign it subgeneric rank under that genus, but the 

 contour of the shell, and the difference in dentition are, it seems, 

 sufficient justification for giving it full generic value. 



A comparison of my figure of the dentition with that of 

 Adeorbis, by Fischer,^® suggests that perhaps Button's reference 

 of his species to that genus was much more correct than his refer- 

 ence of it to Fossarina ; it may be that Risellopsis forms a 

 connecting link between Risella and Adeorbis. The fact of the 

 operculum being corneus in the one and calcareous in the other, 

 need not be considered antagonistic to this, as evidenced by the 

 close relationship of Polinices and Natica. 



Tt is possible that Risella (Peasiella) caledonica, Crosse,^*" is 

 referable to Risellopsis, but as I am unable to examine either the 

 radula or the operculum, I refrain from saying definitely that it is. 



To the more thoroughly appreciate the characters of Risellopsis, 

 it was found necessary to obtain the radula of Risella; while 

 doing so, anatomical difierences between it and Littorina were 

 observed. I hope shortly to describe these differences at length 

 in a paper devoted to the subject. 



As Risellopsis varia has been but briefly described, and never 

 figured, I append the following descriptions and figures : — 



Risellopsis varia, Hutton. 



(Figs. 30, 31, 32). 



Adeorbis varia, Hutton, Cat. Marine Moll., Col. Mus. and Geol. 



Surv. N.Z., 1873, p. 35. 

 Fossarina varia, Hutton, Man. N.Z. Moll., Col. Mus. and Geol. 

 Surv. N.Z., 1880, p. 79. 

 Shell rather solid, opaque with translucent spaces, turbinate, 

 perforate, of three and a half whorls ; whorls rounded. 



n Hutton— Cat. Marine Moll., Col. Mus. and Geol. Surv. N.Z., 1873, p. 



35, (as 4deor6is); Man. N.Z. Moll , 1880, p. 79, (as Fossarina). 



'5 Fischer— Journ. de Conch., 1885, p. 16G, pi. ix., f. 1 -4. 



16 Crosse— Journ. de Conch., 187-4. p. 206; J875, p. 139, pi. vi., f. 6 (as 

 Fossarus) ; Tryon — Man. Conch., ix., 1886, p. 263 (as Peaseiella). 



