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W. M. Wheeler 
out into the body-cavity, where they may be detected among the 
maturing ova and still coiled up wdthin small masses of a plasmatie 
substance [sp). 
In one of the three specimens the testes are much reduced, and 
this leads me to infer that they may ultimately disappear completely 
when the last spermatogonia have developed into spermatazoa, and 
that a purely female phase may supervene in the life of M. hellt. 
This inference gains in probability with the observations on the next 
species to be described. I deem it very probable that in an earlier 
stage the species may be protandric like cirriferum^ glahrum etc. ; 
at least there are no facts to stand in the way of such a siip- 
position. 
7. Jf. cryptopodium n. sp. 
Of this species I have seen only a single specimen taken from 
a smooth pea-shaped calcareous cyst on the arm of a specimen of 
Metacrinus interruptus^ Carp. The label was marked »Indian Museum, 
Calcutta». The Myzostome was terra-cotta colored and 3.5 mm long. 
Lateral and dorsal views of the specimen are shown in PI. 11 Figs. 35 
and 36. Like M. heilig M. cryptopodium has tbe lateral portions of 
the body reflected dorsally, but this reflection is more complete, in- 
volving also the postero-lateral edges. The two edges which overlap 
dorsally have a few feeble rudiments of cirri anteriorly. I could find 
traces of only two pairs of suckers, corresponding to the third and 
fourth pairs of other species. The ventral surface is marked on 
either side (Fig. 35) by five deep furrows, the most anterior being 
the shortest, the most posterior the longest and deepest. Sections 
show that the small parapodia are concealed each at the bottom of 
one of these furrovvs. 
A comparison of a cross-section (Fig. 37) through the middle of 
the body with the corresponding section of J/. helli represented in 
Fig. 33 is very instructive. The posterior end of the retracted pharynx 
[ph] is shown where it protrudes into the cavity of the intestine. The 
intestinal ramifications [int.r) are more capacious and much less sub- 
divided at their tips than in M. helli. The body- cavity [eoe] into 
w^hich the intestinal ramifications extend appears at first sight to be 
much more extensive, but this is due to the smaller number of ova 
which it contains. In the neighboring sections a few indistinct traces 
of testes were found in the sanie position as the testes of M, helli. 
The large and very distinct ovaries [ov] are ventral to the main 
