STKES : ON HAWAIIAN SPKCIES OF OPEA^. 113 



is not vertical. I have seen about twenty specimens, a few of which 

 are slightly narrower in proportion to the length. This may, very 

 possibly, be the manuscript 0. striolata of Pease. 



3. Opeas Pkestoni, n.var. Hawaiiensis. (Fig. 3.) 



Sah. — Hawaii, Kawailoa, Mauna Loa at 1,500 feet (Perkins) ; 

 Hawaii, Hilo (Henshaw). 



In the "Fauna Hawaiiensis" I referred this shell to the species 

 described by me from Cej'lon. After a careful re- examination of 

 a good series of specimens from both Hawaii and Ceylon, undertaken 

 at the suggestion of Professor Henshaw, there appear to be certain 

 constant differences between the shells collected in the two localities. 

 "Whether these be of specific value or not it is very hard to say, bearing 

 in mind the abnormal distribution of the genus, but they seem worthy 

 of, at least, a varietal name. 



The Hawaiian form is more cylindrical, i.e. the earlier whorls 

 increase more rapidlj' and the later ones less so, the colour is pale 

 yellowish white, whereas the Ceylon shell is a light horn-colour, the 

 texture of the shell is slightly thinner and more transparent, and the 

 specimens that I have seen are, on the average, smaller in size. 



4. Opeas pyegiscus (Pfeiffer). (Fig. 4.) 



I have not as yet seen anything that agrees exactly with the series 

 in the British Museum. Of the shells sent by Mr. Henshaw specimens 

 from Kohala, Kau, approach it most nearly ; also some specimens 

 collected by Mr. Thwing in an extinct crater, Kona, appear to be 

 closely related. Final determination must be reserved, as both sets 

 of shells are immature. 



All figures are taken from specimens in my own collection, except 

 Fig. 4, which is a copy of that given by Pfeiffer. 



