1896.] NATURAL SCIENCES OF PHILADELPHIA. 399 



Reibisch in 1892, as will be more particularly discussed later. Dr. 

 AVolf obtained the following species, mostly represented by a small 

 number of individuals, and too often in an imperfect state of preser- 

 vation. From Charles Island, B. tmifasciatus, nucula, asperatus, 

 mix, nudformis, iishdatus and calvus, known forms, and B. invalidus, 

 venustus, cinereus and nudus, described by Reibisch as new. From 

 Chatham Island, among known species, Wolf found B. incrassatus, 

 rugulosus, achatellmus, chemniizioides, Succmea Bettii, and the fol- 

 lowing supposed to be new: B. terebra, ventrosus var., acutus, curtus, 

 lima, canaliferus, Leptinaria cymatoferus, Helidna Wolfi and Succi- 

 nea Wolfi, described by Reibisch. From Albemarle Island, B. pal- 

 lidus, Simrothi and Pupa munita, all regarded as new by Reibisch ; 

 Indefatigable Island supplied the new B. Wolfi and Pupa clausa 

 Reibisch ; and Barrington Island 5. ('e?i<rosixs Reibisch. These spe- 

 cies will submit to some additions from data furnished by letter 

 through the politeness of Herr Reibisch, who has also sent me for 

 examination a number of his types. 



H. M. S. Peterel, Commodore Cookson, visited Charles Island in 

 1875, obtaining B. mix in numerous varieties, B. tmifasciatus, 

 eschariferus and the Succinea described by E. A. Smith as S. Bettii 

 and var. brevior, in honor of Staff-Surgeon Bett, who collected the 

 specimens. 



In 1888, the U. S. S. Albatross, Captain Tanner, of the U. S. Fish 

 Commission, during her voyage from Norfolk, Virginia, to San 

 Francisco, California, spent a short time in the Galapagos group, 

 and obtained a good many specimens of a few species of land shells, 

 ■which have been discussed by Dr. Stearns in the Proceedings of 

 the U. S. National Museum for 1892. The collection from Chatham 

 Island comprised BuUmulus nux, nxicijormis, amastroides, chemnitzi- 

 oides, Habeli, and Succinea Bettii; from Charles Island B. nux in 

 numerous varieties, rw^/u^osMS, eschariferus, Siphonaria gigas, Onchi- 

 della Steindachneri Semper, and the new 0. Lesliei Stearns ; Albe- 

 marle Island afforded B. nux and the two Onchidiums, while at 

 Hood Island Williainia peltoides was obtained. The Albatross again 

 visited the Galapagos under the direction of Professor Alexander 

 Agassiz in 1891, but no land shells appear to have been collected on 

 this occasion. 



The most thorough and important exploration for land shells 

 which has yet been made is that upon which this paper is essentially 

 based, namely, the expedition of Dr. G. Baur in 1890, in which 



