248 
ON HELIX BASILEUS, BENSON, FROM SOUTHERN INDIA : 
ITS ANATOMY AND GENERIC POSITION. 
By Lieut.-Colonel H. H. Gopwiy-Avsren, F.R.S., ete. 
Read 13th June, 1902. 
PLATE VI. 
Matacotoatsts interested in the generic position of species of Indian 
Land Mollusca are very greatly indebted to Dr. Thurston for the 
trouble and pains he took to obtain an individual of this fine species, 
‘‘a giant among the Testacea of Hindustan,” as Benson writes. 
To Dr. Thurston we already owe our thanks for examples of a number 
of species not only interesting, but valuable, because nothing was 
known of their anatomy, or of their relationships. The very large 
forms are not usually abundant, and their size renders it difficult to 
preserve the animal, unless the collector starts for their habitat 
properly equipped for the purpose. For many years I have been 
hoping to obtain the animal of the species under consideration, and 
I have now to thank my friend Dr. Blanford for entrusting one to 
me for examination, a piece of work which has proved as absorbing as 
was that on another species from the south of India, viz. Ariophanta 
ampulla, described last year in these pages (vol. iv, p. 187). 
The shell of é/elix Basileus was described by Mr. W. H. Benson 
in the Annals and Magazine of Natural History, ser. rm, vol. vii 
(1861), p. 81. He says, ‘‘ This magnificent species (received through 
Lieut. Charles Annesley Benson), measuring nearly three inches in 
diameter, was discovered by Lieut. W. Cox, of the 45th Madras 
Regiment of Infantry.” 
Animal.—General colour a ruddy ochre, the peripodial margin 
streaked with lilac. No parallel grooves above, as in DMacrochlamys 
and most genera of the Zonitide. The general surface of the foot is 
smooth ; seen from above a fine groove runs down the centre of its 
rounded dorsal surface, having fine close grooves leading from it; they 
soon disappear, and the surface is broken up into irregular, small, oval 
or diamond-shaped papille. The sole of the foot is pale ash-grey in 
colour and quite smooth, although the spirit has contracted it into an 
irregular fold on the centre line. The mucous gland is linear and long, 
without any overhanging lobe. The mantle-margin forms a continuous 
