DR. W. B. CARPENTER ON TOMOPTERIS ONISCIFORMIS. 359 
plain tube as far as the first fourteen or fifteen pairs of appendages. It then becomes 
transversely folded and wrinkled, and thus passes, preserving a very even diameter, to 
the end of the body. | | | 
« The cavity of the body contains, floating about between the intestine and the parietes, 
certain rounded free masses. These are made up of other more or less rounded masses, 
flattened when their sides are applied to one another (fig. 9), which have perfectly the 
structure of ova. These ova had a diameter of z37th of an inch, and less. In those of 
the former size the germinal vesicle measured 35th of an inch, and was clear and delicate. 
The germinal spot, vesicular and thick-walled, measured ygs5th of an inch. 
“The appendages are hollow processes of the body, and their cavities are continuous 
with that of the body, as was evident from the passage of the ova from the one into the 
other. They increased in size to the fourth or fifth pair, and diminished again from the 
seventh or eighth. The first sixteen or seventeen pairs consisted of a stout basal portion 
terminated by two divisions, each of which was provided with a flat, vertical oar-like 
expansion. The remaining appendages became smaller and smaller and more rudi- 
mentary. The anterior ones were provided with two conical processes merely, while the 
posterior ones were themselves nothing but short simple processes. There was a short 
space between the last pair of processes, which were mere buds, and the truncated anal 
extremity. | | 
“At the re-entering angle between the second pair of cephalic appendages and the 
narrow neck, there is, on each side, a rounded elevation, from which a sort of band or 
ridge runs back upon the dorsal surface. i 
“On the ventral surface, close to the two rounded elevations, a long, curved, spine-like 
process arises upon each side. In their natural position these two processes lie parallel 
with one another, one on each side of the mouth. i 
“ Aug. 28th.—A small specimen obtained to-day appears to be a male, for it contained 
masses of round cells, each rather more than s¢yoth of an inch in diameter, in the place 
of the masses of ova of the previous specimen; these were perhaps young spermatozoa. 
In other particulars its structure agreed with the for ing.” i 2, 
It is obvious that Professor Huxley’s speeimen must have been in a more advanced | 
stage of development than mine, since it had no fewer than thirty-three pairs of append- 
ages, and was also maturing its sexual organs. His figure and deseription indicate that 
the conformation both of the body and extremities underwent à change at about the six- 
teenth or seventeenth pair; but the transition seems to have been far less abrupt than it 
Was in my specimen; so that he does not appear to have been struck with any very 
decided difference in the conformation of the anterior and posterior parts of the As 
Ånd his figure of one of the appendages of the latter would seem to indicate "ue "— 
more advanced condition these approach more nearly to the type of those of the an , 
than they seemed to me likely to do. 
| 12:34 aeiicunpiotd 
chscholtz, who briefly characterized and 
T. . Se, . 1 
omopteris onisciformis was first described by Es assigning to it a place 
rudely delineated it in the ‘Isis’ for 1825 (p. 735, pl. 9 fig. 9), 
