GENEKAL ZOOLOGY. 27 



Some years ago Mr. Brazier described * a species of Tornafellina from Lord 

 Howe, but from the fact that only one fragment was found amongst our 

 large gatherings from the North Ridge gullies, it must be very rare. In the 

 paper referred to he also described Simpulopsis Mastersi,f one specimen of 

 which occurs in the present collection. 



Equal only in abundance, even if not commoner than the characteristic 

 Helix Sophice, is Bulimus bivaricosus, Gaskoin,J found everywhere under 

 cover, and in immense numbers. Like the Helix, this shell appears to avoid 

 open spaces as a rule, and prefers shady damp situations and the scrubby 

 hill sides where composed of the Coral-sand rock. It is sparingly represented 

 even at the higher altitudes, being reported as seen under the "wall" of 

 Mount Ledgbird. The egg-cases are usually met with at the base of the 

 palm leaf sheaths, between the latter and the stems. There is great varia- 

 tion exists in the thickness of the shell of this species, and I believe it was 

 on a thin shelled variety that Dr. Cox established his Bulimus cuniculinsulce.% 

 It occurs on Eabbit or G-oat Island, and is, as Dr. Cox says, both smaller and 

 lighter than the typical form of the main island. Numbers of gradations can, 

 however, be traced amongst a series of the latter, and it seems more in keep- 

 ing with facts to regard the Rabbit Island shell simply as a variety. 

 This variation in the thickness is carried to the extreme condition in the sub- 

 fossil examples of B. bivaricosus, in which the shell becomes thickened to an 

 enormous extent, but in this case even gradations can be traced to the existing 

 condition of the species. This variety I purpose calling B. bicaricosus, var. 

 solida. We may now pass to the operculate section of the Pulmonifera 

 consisting of three genera and seven species. Two forms are common, 

 Omphalotropis exquisita, Pfr.,|| and Diplommatina Macgillivrayi, Pfr.,^[ both 

 originally collected at Lord Howe by the late J. Macgillivray. Two other 

 species of the last genus were collected both by Macgillivray and ourselves, 

 D. capillacea, Pfr., # * and D. Cantori, Pfr.,tf but are not as plentiful as the 

 former shells. A fourth species of Diplommatina is said by Dr. Pfeiffer to 

 exist on Lord Howe, called by him D. cliordata,%% but we did not obtain it. 

 The list may be concluded by one specimen of Realia. 



Under very trying circumstances we were fortunate enough to discover 

 fresh water non-pulmoniferous forms at a considerable height on the 

 eastern flanks of Mount Ledgbird in steep gullies running down to the shore. 

 These consisted of two species of Bythinella, crawling over stones. One, a 

 spirally striated shell, with a deep suture, will be described as B. 

 Wkiteleggei, by Mr. Brazier, and the other as B. Bamsaii, as an appreciation 

 of the interest taken in our proceeding by the Curator of the Australian 

 Museum. 



The bivalve mollusca (Pelecypoda) are not largely represented at Lord 

 Howe Island. Within the Lagoon at, and a little below low water-mark, 



* Description of six new species of Land Shells from Australia and Lord Howe's Island 

 Proc. Zool. Soc, 1872, p. 619. 



f Loc y cit., p. 619. 



X Proc. Zool. Soc, 1854. p. 152. 



§ Description of new land shells from Australia and the South Sea Islands. Proc. Zool. 

 Soc, 1872, p. 19, t, 4, f. 3. 



|| A Monograph of the Genera Reilia and Ht/drocena. Proc. Zool. Soc, 1854, p. 307 (=0. 

 Pfeiferi, Crosse). 



H Descriptions of eighteen new species of Cyolostoraacea from Mr. Cuming's Collection. 

 Proc Zool. Soc, 1854, p. 303. 



** Ibid, p. 303. 



ft Descriptions of sixteen new species of Pneuinonopoma from the Collection of H. 

 Cuming, Proc Zool. Soc, 1856, p. 336. 



XX Proc. Zool. Soc, 1855, p. 105. 



