212 PROCEEDINGS OF THE MAEACOLOGICAL SOCIETY. 



to forms inhabiting India and Ceylon. This genus includes a large 

 number of species, although I have been able somewhat to reduce the 

 number of nominal forms, but several of those in tbe list given below 

 are only provisionally referred to the genus. 



The following is the history of the names Xestina and Nilgiria. 



The generic name Xestina was proposed in 1878 by Dr. Georg 

 Pfeffer (Jahrb. Deutsch. Malak. Ges., 1878, p. 257) in a paper entitled 

 " Die Naniniden." No type is mentioned nor is any description 

 given, but in a footnote it is stated that this group (i.e. Xestina) 

 corresponds to the group Xesta of Semper ("Diese Gruppe entspricht 

 der Semper' schen Gruppe Xesta''''). In the course of a discussion 

 contained in the paper on the form of the foot (Fussbildung) in 

 various ' Naninidae ' several species are referred to Xestina. These 

 species are X. Siamensis, X. Isabellina, X. bistrialis, X. ligulata, 

 X. Maderaspatana, and X. resplendens. 



Now it is evident that Pfeffer did not propose simply to substitute 

 his term Xestina for Semper's Xesta, though this is the only 

 intelligible meaning of his footnote as it stands. Then it is important 

 to notice that Semper (" Reisen im Archipel der Philippinen," 2 e Th., 

 Wiss. Res., vol. iii, pp. 55, 68) in 1870, when he raised Albers's 

 subgenus Xesta to generic rank, did not call it a Gruppe or group, 

 but a Gattung or genus, which he divided into three sections, and it 

 was to each one of these sections that he applied the term Gruppen. 



I had already arrived at the conclusion that there was a misprint 

 or omission in the footnote to Pf offer's paper, and that " Gruppe Xesta'''' 

 was a mistake for " Gruppe Xesta 1," when I came across a second 

 paper of Pfeffer's published in 1882 (Abh. Ver. Hanib., vol. vii, pt. 2, 

 p. 13), in which the fact was stated that the error I had ruspected 

 really existed, and that Xestina was proposed for Gruppe 1 of Semper's 

 Xesta (Semper, t.c, p. 48). This group comprised the following 

 species : Xestina bistrialis, X. ligulata, X. Tranquebarica, X. Belangeri, 

 X. Maderaspatana, all of which are Cisgangetic forms. 



The term Xestina had, however, been clearly defined by Von 

 Martens in the Zoological Record for 1878 (published in 1880), 

 vol. xv, Mollusca, p. 62. He there showed that Xestina corresponded 

 to section C of his account of Semper's genus Xesta in the Zoological 

 Record for 1870 (vol. vii, p. 153). This section C was Semper's 

 Gruppe 1. It was in consequence of the definition of Xestina given by 

 Von Martens that, when, in 1880, 1 I had occasion to describe a species 

 allied to X Maderaspatana and X Belangeri, I called it X albata. 



The genus Nilgiria was proposed by Godwin-Austen in 1888 

 (Land Preshw. Moll. Ind., vol. i, p. 253), the type being N. solata, Bs. ; 

 and in 1899 (op. cit., vol. ii, p. 77) he described the anatomy of 

 N. solata, N. Tranquebarica, and N. bistrialis, and pointed out (p. 76) 

 that his genus Nilgiria included the species belonging to Semper's 

 first group of Xesta (Von Martens' group C). Later in the same work, 

 he described the anatomy of N. ligulata, N. Chenui, and N Ceglanica 



1 Journ. As. Soc. Beug., vol. xlix, 2, p. 189, pi. iii, fig'. 3; see p. 245 infra. 



