6 LAND AND FRESHWATER 
it subbaculina, for I cannot find in my collection frem the Khasi 
Hills any Glessula that matches the type in the Henry Blanford 
collection. 
Classification and Distribution. 
Mr. G. K. Gude, in the ‘ Fauna of British India,’ puts Glessula 
into the family Ferussacide (p. 373), immediately following 
the genera Caceliowes, type acicula, Miill., Geostilbia, type 
caledonica, Crosse, and balanus, Reeve, together with a new 
species, G. bensont (p. 375). 
With these genera I cannot agree that Glessula has affinity ; 
the animals are unknown, the shells very different, the 
conditions of life and extent of range very distinct. Range 1s 
an important factor in questions of this kind. C. acicula 1s 
Palearctic, spreading to the far South. Glessula is Oriental 
and in comparison limited in its area of distribution. Commencing 
with Southern India, it is absent from the N.W. Himalaya, 
bordering on the eastern margin of the Palearctic, coming in 
(in Nepal?) in Sikhim and extending through the North-Kast 
Himalaya, Assam with the Assam Range, and thence to Burma, 
China, and Sumatra. All these are forest-clad countries with 
considerable rainfall, or country which was once much more 
forest-clad than at present, before man arrived to destroy the 
ancient forests. The Khasia Hills, with the Jaintia on the Kast, 
Were once much more wooded than they are at present and formed 
a tract of country of great extent. Geost:Ibia balanus, on the other 
hand, may be called a desert species, standing great heat and great 
dryness for months. A knowledge of the animal would be of 
extreme value in every way. I cannot find that it has ever been 
seen alive. 
1 prefer to place Glessula and its subgenera in a family of 
its own, the Glessulide. 
Conchologically Glessula possesses many very distinct characters, 
It comprises shells which have the columellar margin abruptly trun- 
_ cute at the base, which in the majority of the species forms a short 
gutter and holds a part of the mantle near the right dorsal 
margin. A well-defined division with shells of all sizes is found 
having elongate, turreted, and flat-sided shells, the major diameter 
differing little from that of the small aperture. Typical Bacillum 
cassiaca falls under the above shell description, and I shall have to 
refer to this subgenus—it is much more solid and opaque, with 
stronger regular sculpture and larger apex ; the animal (December 
1919) still remains to be described. 
A departure from the Bucillum type of shell character is met 
with in Glessula tenuispira (Plate CLIX. fig. 3); the shell is thin, 
transparent, more or less finely striate, the aperture larger, and 
that and the body-whorl together are much larger than the shorter 
spire above. 
This proportion of parts is intensified in species like Plate CLX. 
fig. 1 burrailensis, fig. 2 do., fig. 3 do., fig. 4 do., fig. 5 var. maawelli ; 
still more in fig. 9 butler’, fig. 14 crassilabris, or what may be 
