318 ON THE ANATOMY AND DEVELOPMENT OF PYROSOMA 
many individuals, this organ is colourless, and that it resembles a 
cellular and transparent globule: it also varies greatly in volume ; 
sometimes, and most frequently, it is of the size of the stomach, 
sometimes five or six times as large.! 
“The nervous system of the Pyrosomata does not appear to differ 
essentially from that of the foregoing animals. There are, in like 
manner, two tubercles, one on each side of the neck of the branchial 
sac. The anterior or superior tubercle seems to give off several 
filaments, of which four ascend on this neck, while the others go to 
the opposite side. The posterior tubercle, which is here inferior, 
though very apparent in certain individuals, is imperceptible in most. 
There arise from it four opaque yellowish or brown vessels, which 
traverse the lower side of the tunic ; they are evidently the four cords 
of the dorsal groove of the Ascidians.2 Along the upper edge, 
opposite the four cords of the dorsal groove, are seen two wide, short 
canals, of a yellow or muddy-brown colour, placed parallel, and so 
closely united that they might be regarded as a single canal, bent like 
a siphon, and extending from the middle of the branchiz to the 
esophagus, where its two extremities end. The interior appears to 
be cellular.’ 
“This organ, which is sometimes empty and transparent, seems to 
me to be analogous to that which M. Cuvier regards as the ovary of 
the Sa/pe, or at least as their oviduct ; perhaps it is, at the same 
time, oviduct and fecundating organ. 
“The ovaries? are orbicular or pyriform, symmetrically opposed 
to one another, and placed on the sides of the neck of the branchial 
opening, between the tunic and the branchial network, which they 
usually overlap. They communicate with two small, sometimes 
coloured ducts, which embrace the neck and descend as far as the 
loop formed by the siphon-like canals. These ovaries contain a 
multitude of rounded, very small, but very distinct ova. : 
“If I do not deceive myself, the manner in which these germs 
arrive at maturity is very curious. It would appear that while very 
small they become detached, one by one, from the ovary, and are 
1 Savigny has here clearly confounded the testis and the ovisac together under the one 
name of ‘foie.’ What he calls the ribbed organ is the testis; the cellular globule is an 
advanced ovisac. 
2 The ‘anterior tubercle’ is the nervous ganglion ; the posterior merely the anterior end 
of the endostyle, which is described as the ‘ cords of the dorsal groove.’ 
* This ‘organ’ is the intestine of Lesueur, and, as I have said above, is nothing but a 
mass of blood-corpuscles accumulated in the hypopharyngeal sinus. 
4 These are not the ovaries, but probably, as I have already said, renal organs. What 
Savigny calls their ducts seem to be the lower parts of the peripharyngeal ridges. 
