DRS. CARPENTER AND CLAPAREDE ON TOMOPTERIS ONISC1FORMIS. (>3 
" rosettenformiges Organ" which was noticed byLeuckart and Pagenstecher upon the two 
first pairs of appendages of their T. quadricornis, and which is affirmed by them to be 
entirely wanting in T. onisciformis . This is alike remarkable for its form (fig. 9), which 
somewhat resembles that of a melon, and for its colour, which, being a bright sulphur- 
yellow, distingnishes it from the coloured spots noticed in the former memoir, these 
being of a reddish orange. In the very young specimen already adverted to, these organs 
presented themselves at the bases of the pinnuhe (fig. 11. c, d) of the two most developed 
pairs of members. Of their nature and purpose we have not been able to form even a 
probable guess. 
It is in regard to the caudal prolongation of the body, and the organs which it contains, 
that we have the most novel and important information to offer. We can now state with 
certainty that the large specimen represented in Plate LXII. figs. 6 & 7 (vol. xxii.) was a 
male,— the eight pairs of ovoidal bodies from which the rudimentary pinnules appeared to 
spring being really the testes, which occupy the parts of the perivisceral cavity that an 
prolonged into the short lateral appendages whereon these pinnules are really borne. Each 
testis (PI. VII. fig. 2. a, a) is an undivided sac, whose cavity, when the organ has attained 
its maturity, is almost entirely filled with a mass of spermatozoa. The individual parts 
of this mass are in continual movement upon each other, their motion being kept up 
chiefly, if not entirely, by the action of the cilia clothing that part of the inner wall of the 
testis which is near its external orifice. Each testis (fig. 3) can discharge its content* 
either externally through an orifice (a) in the wall of the lateral appendage within which 
it is lodged, or internally through another orifice (b) into the perivisceral cavity, 
the external orifice is distinct from that of the larger, ridged rosette (c) of the ciliated 
canal, we feel ourselves able to afiirm with certainty ; but we are not equally sure of its 
distinctness from that of the smaller rosette in its neighbourhood. The internal orifice, 
by which the spermatozoa escape into the general cavity of the body, can only be seen 
occasionally; and we are disposed to think that it is formed only when the contents of the 
testis are fully matured. Whenever we caused these to be discharged by pressure, it was 
through the external orifice that they escaped. 
The spermatozoa of Tomopteris (fig. 4), which we had abundant opportunities of ob- 
serving are Dsouliar in havine two fla<?ella— a feature which, although general among 
Th 
peculiar 
© uwv ~~^ 
the antherozoids of the Algse, is very rare (if not unique) among the spermatozoa of ani- 
mals *,— and also in being able to move in either direction with apparently equal facility. 
It will presently appear that the testes occupy exactly the same place in the lateral 
appendages of the caudal prolongation as the ovaria do in those of the body generally, 
the chief difference in their apparent positions arising from the smaller size of the lateral 
appendages in the former region, and from the more complete occupation of the cavity ol 
these appendages by the oval sacs of the testis. 
alis 
(P 
exit from the mouth of Pedicellina Belgica of numerous minute pear-shaped bodies, each having «a little tubercle at 
twice 
its larger end, around which are set a few (about four or five) long cilia or setse, 
These are not used for vibratile action, but as oars slowly waved through the waters 
11 
Although 
us 
