GODWIN-AUSTEN: ON HELIX BASILEUS, BENS. 251 
E. Moellendorfi, are in no sense related to that genus. In these 
Bornean forms the most striking difference from Macrochlamys is seen 
in the genitalia, in the form of the amatorial organ and its dart. We 
find this same structure of the amatorial organ is not confined to the 
genus Hverettia, but recurs in species with very differently formed 
shells, such as Dyakia Hugonis, D. Rumphii, and D. rareguttata, 
which Semper included in Ariophanta, and thus, in fact, we have 
in the Malay Archipelago a local generic group very similar to one 
found in southern India. 
It may be noted I do not accept the subgeneric title of Xestina 
for the southern Indian forms, because a genus should be properly 
described, and a type-species indicated. If this rule were always 
followed much uncertainty and confusion would be avoided. 
The history of Xestina may be summed up as follows :— 
Albers: ‘‘ Die Heliceen,’’ 1860, pp. 50, 51. Created Xesta, gave 
a description of the shell characters, and made two divisions :— 
(a) Testa solidula; type, Nanina Stuartiea, Sow., from Celebes. 
(b) Testa pellucida; type, NV. citrina, Linn., from Amboina. 
Semper: ‘‘ Reisen im Archipel der Philippinen,” 1870, pp. 55-68. 
Divided Xesta into three groups, unnamed. 
Pfeffer: Jahrb. Deutsch. Malak. Ges., 1878, p. 257. Indicated 
Xestina, did not describe it, but in connection with it mentioned 
first and more particularly the species WV. Svamensis, thereby 
indicating this species possessed the characters of his new genus 
better than any other; next he alludes to WV. Lsabellinus (since 
shown to be a Huplecta) and four other species. 
Pfeffer: Abh. Ver. Hamb., vol. vii, pt. 2 (1882), p. 138. Stated that 
Semper’s group of five South Indian species comprised the 
genus Xestina; but neither the characters of the genus nor 
the type are indicated. 
Godwin-Austen: ‘‘ Land and Fresh-water Mollusca of India,” 
vol. i (1888), p. 253. First refers to the genus Milgiria, 
giving solata, Bs., as the type; he described the characteristic 
points of the genus and the anatomy of the type in the same 
work, vol. 1 (1898), pp. 77, 78, since found by him to 
agree with two species, Vanina Tranquebarica and NV. bistrialis, 
which are included in Semper’s group of Xesta above alluded to. 
Touching Pfeffer’s first work of 1878, the anatomy of WV. Szamensis 
has, I believe, not yet been described, but supposing that it should 
turn out to be peculiar and of generic value, would it not be entitled 
to Pfeffer’s name Xestina? He at the time was discussing the form 
of the foot in the Naninide, and did not carry his investigations with 
reference to Siamensis much beyond that poimt; he may have had 
the form of the shell also in mind, but it is impossible now to interpret 
exactly, owing to the lapse of time and the work done since by others, 
what Pfeffer understood as the typical characters of Xestina, but it 
seems to me that the species Szamensis, the first he selected, expressed 
them most forcibly at that period. 
