LOXOSOMA LOX ALINA AND LOXOSOMA SALTANS. 119 
entirely beneath the surface rather than raised above it, but 
probably all such organs may be said to be generally homo- 
logous. In L. loxalina they have undergone a special 
development and differentiation, and though projecting from 
the surface, do not stand out so clearly as in L. Davenporti 
or ill L. saltans, the second species to be described here. In 
all specimens that I have examined these organs are generally 
Similar; they occupy more or less corresponding positions, 
and are differentiated in like manner. There are usually two 
pairs on the calyx and two pairs on the body, and they tend 
to give the animal a somewhat angular appearance. Some- 
times extra pairs occur on the body. There are none on the 
stalk, which is sharply marked off from the body. In L. 
Davenporti they are borne about the spot where the body 
passes into the stalk. Although glandular is a convenient 
term to use, there is no sign of any secretion exuding from 
them. Figs. 1, 15, 16 and 17 indicate clearly euough the 
structure of these organs, but their function must remain 
for the time being a mystery. Fig. 1 represents the most 
usual condition. I have never found less than the four 
pairs here indicated, but I have in some specimens seen 
additional pairs. The two pairs on the edge of the calyx are 
less prominent than the others, and are not very different from 
the unicellular glands of Salensky, L. tethyae. The lower 
pairs are either connected with, or lie in close juxtaposition to, 
rows of large deeply stained cells (tigs. 1, 3, and 6 [k.]). On 
the body there are two pairs, the upper of which is on the 
ventro-lateral surface at the level of the lower margin of the 
two appendages of the stomach. The lowest pair of all is 
different from the rest, and is never absent. Whereas the 
Olliers vary a good deal in form and degree of development, 
this lowest pair is constant. Each organ consists of a group 
of long cells, the nuclear ends of which are deeply imbedded 
in the body, and the outer ends, projecting a short distance 
beyond the surface, form a conical eminence with a small 
crater-like depression on the centre. Fig. 17 (a.) represents, 
in diagrammatic form, the structure of these and the other 
