22 LIVERPOOL BIOLOGICAL SOCIETY. 
the larval Tunicata as having been probably evolved 
independently in that group, and as having no phylo- 
genetic relations with the corresponding organs of any 
other group. 
II.—THE Pituitary Bopy ork HypopHysis CEREBRI. 
In 1867 Hancock* discovered in the Tunicata a glan- 
dular body lying below the single nerve ganglion. In 
1876 Ussowt investigated the structure of this body more 
minutely, and traced a delicate duct leading from its 
anterior end to open into the front of the branchial sac. 
Julin, in a very important paper,t published in 1881, 
gave the results of his examination of this subneural gland 
and its duct in a number of Simple Ascidians, and showed 
that the so-called dorsal or olfactory tubercle placed upon 
the anterior dorsal part of the branchial sac contains the 
complicated opening of the duct from the gland (Pl. IL., 
figs 15 dt.) 
Julin comes to the conclusion that the subneural gland 
in the Tunicata is the representative of the hypophysis 
cerebri of the vertebrate brain (Pl. I., fig. 1, h.), and 
bases this homology upon, (1) its glandular structure, (2) 
its position on the ventral surface of the ganglion (brain), 
and (8) its connection with the anterior end of the 
branchial sac (pharynx). It is suggested, both in a second 
paper published in the same year, and also in subsequent 
memoirs by H. van Beneden and Julin, that the hypo- 
physis cerebri functioned originally as a renal organ, and 
* Jour. Linn. Soc., Zool., vol. ix., 
+ Contributions to our Knowledge of the Organisation of the Tunicata (in 
Russian.) Imper. Soc. of Nat. Sc., Moscow, vol. xviii. 
{ Recherches sur l’organisation des Ascidies Simples—Sur | Hypophyse, &c. 
Arch. de Biol., vol. ii., p. 59. 
