4 Tun . 
.“VI. TUN1GATA. 
b. Anatomy. 
Winiwarter gives his observations on the structure of the gland 
ramifying on the walls of the digestive tube in Corella and Phallusia. 
He confirms the statement of previous observers that the gland opens 
into the stomach, and has no connection with the blood system. In some 
species there are multiple ducts. He considers it a digestive gland. 
Seeliger, in his account of the Pyrosomas of the Plankton Expedition, 
gives a good description of the structure of a Pyrosoma colony, and full 
anatomical and histological details of all the systems in the body of an 
Ascidiozooid. 
Sluiter gives various anatomical details in his descriptions of both 
simple and compound Ascidians from Australia. 
Klaatsch has an account of the Appendicularian ectoderm, and of the 
activities of the nuclei of the remarkable cells which produce the modified 
test known as the Appendicularian “ Haus.” 
Metcalf gives a set of studies on various interesting points in Tuni- 
cate morphology — such as the subueural gland and its relation to the 
ganglion, pharyngeal and cloacal glands in Cynthia , development of testis 
in Salpa, &c. 
c. Embryology. 
In Coodsiriu dura, n. sp., Ritter finds that the budding is pallial, as 
in Botryllus, but is not found in the adults, as the bud becomes severed 
vory early. He finds that the neuro-hypophysis is formed from the 
dorsal endodorm. 
In Pvrophom annectens, according to Ritter, the cavity of the partition 
of the stolon is connected with the left peribrancliial cavity. There is 
no epicardium, and the nervous system and hypophysis are formed from 
the endoderm. 
Driescii, in investigating the effect of experiments on developing 
embryos, has found that he gets from isolated blastomeres of the second 
stage not half embryos, but whole embryos of half the usual size. 
Hill states that in the egg of Phallusia mammillata there are 
peither egg astrospheres nor egg centrosomes ; both these structures are 
brought into the egg by the spermatozoa, and are derived from its middle 
piece. There is consequently no “ quadrille ” in the early development. 
The nucleus of the ovocyte starts with 8 chromosomes, which then divide, 
and 8 pass out with each polar body. 
Lefevre, in his account of the budding of Perophora , supports Ritter 
in the view that the bud is attached to the stolon by its left peribranchial 
sac, but differs from Ritter in his account of the duration of that attach- 
