188 LAND AND FRESHWATER 
chologia Indica’ renders them eften quite unsuited for reliable 
reference or make clear any specific classification, for very often only 
one view, and that not the most important, is given. In the case 
of plate ciil. the shells are represented from every possible point of 
view, and are positively wrong in detail. I therefore hope in time 
to figure the greater number of this genus in a similar way to those 
now given ; and to do this properly it is necessary to give three views 
of each species, and sometimes four, to show clearly the differences 
that exist between such closely allied forms. Itis a heavy task, and 
one that Stoliczka, with Mr. Blanford’s assistance, had hoped to carry 
out in the whole family of the Cyclophoride. If I can accomplish 
a part of this work, it will, I trust, lessen the labours of future con- 
chologists, and show how beautifully the law of Evolution is exem- 
plified by these varying forms. 
I have no drawing of the animal taken from life, as they are not 
easy to observe, being very shy ubout coming out. The eyes are 
small, and the tentacles not so long and thin as in Diplommatina, 
Plate LI. fig. 3 is taken from a spirit-specimen of A. nagaensis, 
enlarged four times. 
The lingual ribbon given in fig. 4 is that of A. bicrenatus, one of 
the larger species, and very similar to A. ingrami. From this we 
find that in Alyceus the form of arrangement is 
3 —1— 3 
OED 2 em ote tone 
all the uncini being 5-cuspid, with the exception of the outer, on 
which I could only detect 4. It may be noticed that in the drawing 
the 5 cusps are not shown in eyery instance; but it must be 
remembered that they can only thus be seen owing to the toothed 
edges being strongly curved, both longitudinally and laterally. The 
uncini of this species are peculiarly spreading and fan-like, especially 
the first and second laterals. 
There is a slight scar of a semicircular form present on the surface 
of the branchial sac, which corresponds in position with the internal 
orifice of the sutural tube. This indicates the rudimentary nature 
of the branchial tube in this genus. It is very short, and evidently 
by its margin the sutural tube is formed, for this shows successive 
layers of deposition. After the animal has reached a certain stage 
of development (and this stage is perhaps the corresponding one in 
Diplommatina, at the formation of the constriction) this ceases, and 
the whole anterior portion is formed by the edge of the mantle alone. 
Alyceus bembcw is a species with a very short but stout sutural 
tube; an examination of several species showed that close to the 
branchial chamber there is a divarication on the upper side, short 
and corresponding with the external tube, but opening into the 
chamber; the tube is completely closed on the other or posterior 
end. ‘This must be homologous to the tube of Streptaulus. 
It is somewhat difficult to understand how the formation of the 
sutural tube is effected. The position of the internal orifice, so 
different in Lthaphaulus and Alycaus, rather complicates the elucida- 
