Miscellaneous. 71 
Brooks attributes their real function to the genital cord and the 
endodermic tube of the Salpe ; but he does not recognize a true 
alternation of generations in the Salpew. Ova being visible in the 
genital cord of the stolon before the different individuals of the chain 
are distinct, he concludes from this that the so-called agamic form 
is a female producing by gemmation not hermaphrodites, but incu- 
batory males, each containing an ovum. 
Todaro did not recognize the fact of the original distinctness of 
the four mesodermic cords; he described a homogeneous middle 
layer, which, originating from a germoblast, would form the entire 
body of the bud to the exclusion of the endodermic and ectodermic 
tubes. As the germoblast is, with him, the equivalent of the ovum 
itself, the aggregated individuals which originate from it would be, 
not the sons but the younger brothers of the solitary individual, and 
there would be in the Salpe@ neither an alternation of generations 
nor true gemmation. 
My observations enable me to confirm and complete the state- 
ments of Kowalevsky ; they also compel me to support the old 
theory of gemmation and the alternation of generations. 
If in a very young solitary embryo of Salpa democratica mucro- 
nata we examine the germinal point, we see a thickening of the 
ectoderm, against which a diverticulum of the endoderm of the 
parent abuts internally. In front, towards the placenta, there is 
a small transparent mass of mesodermic cells, the origin of the 
neural cord; behind, towards the clceoblast, another more volumi- 
nous one, the origin of the genital cord; and lastly, on each side, a 
thickening is attached directly by a long peduncle to the lateral 
lamella destined to form the muscles of the solitary embryo ; these 
are the rudiments of the lateral cords. Their connexion with the 
muscular plates is at first very distinct ; subsequently the attach- 
ments break and return upon themselves, and it is no longer possible 
to distinguish any thing of them. Upon this point alone my obser- 
vations are in disagreement with those of M. Kowalevsky, who 
makes the lateral cords originate from the cloaca of the parent ; the 
lateral cords, at least in Salpa democratica, originate neither from 
the cloaca nor from the pericardium, but from the muscular lamelle. 
In the section of a young stolon the lateral cords appear as two 
homogeneous cellular masses; later on each of them splits into a 
hollow cloaca, cord and a mass of mesodermic cells. These cells 
multiply greatly, and form the lateral or muscular plates of the 
buds. Further, each segment of the cloacal tube gives origin directly 
to the cloaca of each bud. As to the central endodermic tube, Brooks 
is right in his description of the sacs which it emits at each side, 
and which serve as the origin of the branchio-intestinal tube of the 
buds. These sacs, enveloped and often masked by the muscular 
plates, are none the less recognizable in properly made sections. 
In the Salpe, as in the Pyrosomata, the endoderm, the ectoderm, 
and the mesoderm of the bud are therefore derived from the corre- 
sponding lamelle of the parent, and serve to form the same organs. 
