122 BULLETIN OF THE 
are therefore strictly ofan Astrophyton type, and discharge their products 
into the body-cavity, which is continuous and uninterrupted by radi- 
ating partitions. 
Astrogomphus might very well be called an Astrocnida whose arms 
do not fork ; and we should expect a genus 80 closely allied to have a 
similar internal structure. And so it is. The arrangement of the 
organs of digestion and reproduction is entirely comparable, except that 
tho folds of the stomach are less complex and numerous. 
Ophiocreas cedipus brings us a long step nearer the true Ophiurans. 
An opening, somewhat inclined from the vertical, through the base of an 
arm and the outer corner of tho disk, is sketched in Fig. 7. The integ- 
ument of the arm, cut through, on the side, is lifted and thrown back, 
while the side of the disk is wholly cut away. Above the arm-bones, at 
the base of the arm, lie the double-lobed spermaries, 8, 8, long, cylindri- 
cal, smooth bodies, a little curved, and tapering at each end. On the 
opposite side of the arm lies a corresponding pair. The genital open- 
ing, no, enters a spermatic pouch, or bursa, separated from the body- 
cavity, as in Ophiurans. An extension of the lining membrane of this 
bursa encloses the spermatic lobes, 8,8, which discharge into it by a 
pore at their inner end. I have already remarked (Bull. Mus. Comp. 
Zoól, VI. 2, p. 66) that the ovaries of this species lay in the same 
position, at the base of the arm. I made, however, a mistake as to the 
“ large eggs which are about .7 mm. long.” They are not eggs, but 
clusters of eggs, each wrapped in its membrane and comparable to those of 
Astrogomphus. The position of the genital organs, though curious, is 
not so exceptional as might at first appear. Among true Ophiurans, 
the space between the stomach and the sides and roof of the disk-wall is 
crammed with these organs when gravid. In Ophiocreas, however, not 
only is the disk small, but its body-cavity is limited to the perihzemal 
canal and to a sinas over each arm. Everywhere else the stomach ad- 
heres to the body-wall; therefore the genital organs are, as it were, 
forced into the space between the skin of the arm and the arm-bones. 
The dissection of a female Ophiocreas (an undescribed species from 
the “Blake” dredgings) demonstrated the homology of the genital or- 
gans with those of Ophiurans. There were two long lobes, or tubular 
membranous bags, on either side of the upper surface of the arm. 
These were in process of discharging their eggs, which takes place by 
the breaking up of the egg-clusters and the passage of the eggs to the 
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inner end of the bag, where they go, through a pore, into the bursa, 
which is merely a lobed indentation of the disk-wall, and is even some- 
