392 THE TERRESTRIAL MOLLUSCA INHABITING 



L, FKATERCULA, Pease. 



Helix sculptilis, Pease, Proc. Zool. Soc, 1864, p. 669. Pfeiffer, Mon. Hel., v. p. 217. 



Helix fratercula^ Pease, Amer. Jour, Conch., 1867, p. 104. Pfeiffer, Mon. Hel., vil. p. 253. 



Paetal, Cat. Conch., p. 94. 

 Pitys fratercula, Pease, Proc. Zool. Soc, 1871, p. 475. 

 Patula sculptilis, Schmeltz, Cat. Mus. Godeff., v. p. 94. 



Mr. Pease's type specimens were collected by Dr. Dean at Mangaia, and, sub- 

 sequently, I obtained numerous examples in the same locality, as well as at Raro- 

 tonga, Aitutaki, and Atiu. It is probably diffused throughout the group. It is 

 confined to the low lands near the sea-shore, where it occurs in great numbers in 

 forests. 



At Rarotonga they attain a larger size than found elsewhere, and the spire is 

 frequently more elevated than mentioned by Mr. Pease. Specimens now before 

 me measure seven millimetres in diameter by five in height. Mangaia examples 

 are uniform luteous horn color, and at Atiu, where they are smaller, they are 

 darker and frequently obscurely variegated with reddish-brown. 



It is surprising that Mr. Pease should have overlooked the very conspicuous 

 internal lamelliform teeth in the palate, of which there are always two, and more 

 frequently three, between the periphery keel and columella, which latter is also 

 furnished with a spiral fold, though not alluded to by the above author. 



The laminae are constant during the different stages of growth, but in adult 

 shells are only present in the two last whorls, the preceding ones being absorbed 

 by the animal. 



Rarotonga examples are cretaceous or horn color, sometimes beautifully varie- 

 gated with stripes and tessellations of a reddish-brown color. The ribs in passing 

 over the acute prominent keel give it a beautifully corded appearance. 



The habitat " Gambler" in Pfeiffer's Mon. Hel., vol. vii., is erroneous. 



L. CAVERNULA, Garrett. 



Fitys caucrnwZa, Garr., Amer. Jour. Conch., 1872, p. 226, PI. 19, fig. 16. 



Patula cavernula, Schmeltz, Cat. Mus. Godeff., v. p. 94. 



Helix cavernula, Pfeiffer, Mon. Hel., vii. p. 568. 



Found plentifully in the mountain ravines, and is peculiar to Rarotonga. 



It is closely related to the preceding species, but may be distinguished by its 

 darker color, smaller ribs, less prominent keel, and the shallow groove immediately 

 above the revolving keel is not so conspicuous. In a careful comparison of numer- 

 ous young examples of different ages I remark the umbilicus is considerably 

 broader in cavernula than in fratercula. 



