348 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



these two individuals the communication of the gland with the ciliated 

 funnel had been lost and the secretion of the gland could pass out only 

 through the lateral communications with the peribranchial chamber. 



In Molgula ampulloides Van Beneden (1) found the duct enlarged 

 into two lateral chambers which are significant in this connection. 



In pyrosoma the funnel is produced backward into a thin-walled 

 canal that lies ventral to the ganglion, close pressed to its ventral sur- 

 face. Seeliger (16) and also Lahille (10) figure a ventral evagination of 

 the duct, with thicker walls than the rest, that seems to be homologous 

 with the ascidian gland. 



In doliolum, according to Uljanin (20), we find on the antero-ventral 

 side of the ganglion a wart-like, solid process of nerve cells connected by 

 a small hollow tube with a typically developed ciliated funnel. In the 

 young doliolum the wart-like process from the ganglion contains a 

 cavity of considerable size, which is continuous with the lumen of the 

 funnel through the hollow tube. The cells of the tube in the young 

 individual resemble the ganglion cells; but during the growth of the 

 animal the tube elongates and, as its cells do not increase correspondingly 

 in number, they are drawn out into flat pavement cells forming a thin, 

 interrupted, epithelial wall around the slight central cavity of the tube." 

 The neural membrane is continuous over the tube to the funnel, forming 

 the basement membrane for the epithelial cells of the wall of the tube. 



There are points in the development of the subneural gland and its 

 duct in the ascidians, pyrosoma and doliolum that are of importance 

 in connection with these organs in salpa. In pyrosoma and doliolum 

 these organs are at first merely the anterior opening of the canal of 

 the central nervous system into the pharynx. In doliolum the posterior 

 portion of this canal is obliterated, but a portion of it persists till a late 

 period in the wart-like, antero-ventral process from the ganglion. 1 The 

 canal with its walls is represented in the adult by the process from the 

 ganglion, the ciliated funnel and the hollow tube connecting them. 



The canal of the central nervous system of the embryo pyrosoma 

 opens freely to the pharynx. 2 This canal and its walls are represented 

 in the adult by the ciliated funnel and its posterior prolongation that 

 lies along the ventral surface of the ganglion, the ganglion being a 

 secondary formation derived from the dorsal cells of the posterior part 

 of the canal of the central nervous system. It arises at a compara- 

 tively late period by the proliferation of the cells of this region. 3 Accord- 



1 B. Uljanin (20). ' Oswald Seeliger (16), also W. Salensky (14). 3 L. Joliet (7). 



