Morse.] 346 {March 19, 
vein. He says, “ Veine et artére sont exactement paralléles Pune & 
Pautre. Dans toute la longueur de la branchie, ces deux vaisseaux 
sont mis en communicateur par une double série d’anses vasculaires 
qui passent dans la couche sous-cuticulaire et qui subissent avec la 
plus grande facilité Vaction de leau chargée d’oxygéne 4 travers la 
cuticule tres-amincie.’ 1 
He denies, however, the independent contraction of the ampulle, 
but says there is a rhythmical contraction of the whole branchia, 
Quatrefages, to the contrary, notwithstanding. 
In the family Serpule, Claparéde finds features remotely resembling 
the description of Quatrefages, where in these Annelids “l’artére se 
continue directement dans la veine 4 la base des branchies, et de leur 
point de réunion part un vaisseau unique qui pénetre dans chaque 
rameau branchie.” In Discina I have not been able to discover the 
slightest trace of these ampulle, though the pallial sinuses are very 
prominent; and the central partial partition of ciliated epithelium 
which induces the flow of the circulating fluid in these parts, are as 
distinctly marked in Discina as in Lingula. In the other Brachio- 
pods the prominence of the pallial sinuses, with their diaphanous 
walls, must be regarded as a respiratory organ. In all the Brachio- 
poda the cirri of the arms must also share with the pallial membranes 
in this function. 
Genital Organs. 
Under this head we study the ovaries, oviducts, or segmental 
organs, and spermaries. In the Annelida, according to Claparede, 
the sexual elements, in course of growth, form ruffs all around the 
vascular axes. 
In all cases the ova, when arrived at maturity, detach themselves 
from the ovary to float freely in the perivisceral cavity, where they 
are afterwards gathered up by the ciliated mouths of the segmental 
organs, and discharged by them. — 
This is precisely the case in the Brachiopoda. In Discina the bor- 
ders of the.delicate vascular membranes are thrown into conspicuous 
ruffs by the development of the ova. In Lingula the ovaries are 
intimately bound to the same membranes. In Terebratulina and 
Rhynchonella they not only gather about the large vascular sinuses in 
the pallial membranes, but hang in clusters from the genital bands 
1 Soc. de Phy. et d’Hist. Nat. de Genéve. Tome xix, 2d part, p. 381. 
