Miscellaneous. 455 
from Europe and America, are land birds, while all from the Creta- 
ceous are aquatic forms. The four oldest known birds, moreover, 
differ more widely from each other than do any two recent birds. 
These facts show that we may hope for most important discoveries 
in the future, especially from the Triassic, which has as yet furnished 
no authentic trace of birds. For the primitive forms of this class 
we must evidently look to the Paleeozoic.—Amer. Journ. Science, 
Nov. 1881, pp. 837-340. 
Contributions to the Natwral History of the Compound Ascidia of the 
Bay of Naples. By Dr. A. Detia Vater. 
The author in the first place carefully describes his genus Distaplia. 
In this genus the colony is pedunculate or sessile ; the individuals, 
arranged in branched coenobia, have the form of Didemnide with an 
ectodermic process. The branchial sac is furnished with four series 
of fissures ; the stomach has smooth walls; the heart is placed at 
the level of the intestinal loop; the sexual glands are situated on 
the right side and rather above the heart. The testis is developed 
before the ovary, and in all the individuals of the colony at the 
same time, so that the colonies are always formed entirely of male 
or of female individuals. The mature ova are coliected in the cloaca, 
whence they fall into a peculiar diverticulum, which is developed for 
this purpose and afterwards separates from the animal. The larve 
are gigantic, and already produce buds. ‘The formation of a new 
bud commences by eversion of the parietal lamella of the peritoneal 
sac at a short distance from the end of the endostyle. The bud 
very soon separates from the maternal individual, and migrates 
towards the peripheral parts, dividing by scission, and thus giving 
origin to new individuals, which increase the colony. 
In connexion with the structure of the tail of this large larva the 
author gives an account of the observations of other writers on the 
axial cord which is seen in the tail of these larve, and shows, by 
means of transverse sections, that this cord, considered hy Kowa- 
levsky, Kupffer, &c. to be formed of solid gelatinous material, is, instead, 
merely a cylindrical canal full of a transparent and colourless liquid, 
which is perhaps the same liquid that bathes the surrounding 
cellular elements. 
The author then proceeds to the exposition of his anatomical 
researches. He has observed that in the living ectoderm amceboid 
cells move about in the common mantle, thus confirming a previous 
observation of Hertwig’s. He describes very earefully the general _ 
structure of an ascidiozooid, which he finds to be formed of an 
internal endodermic sac and of a bilobed peritoneal sac, interposed 
between the two primary sacs. The peritoneal sac communicates 
on the one hand with the endoderm by means of the branchial 
fissures, and on the other with the exterior by the cloacal siphon. 
The muscular fibres are situated between the parietal lamella of 
the peritoneum and the ectoderm. The heart and the sexual glands 
