Notes on the morphology of the Tunicata. 539 



of the appearance of the gland in Ascidians, Pyrosoma or Boliolum 

 is to be seen. There are present, however, two structures beneath 

 the ganglion, which are glandular in their nature and which, in spite 

 of their peculiar form, there is some reason to believe may be related 

 to parts of the neural gland in other Tunicata. These are the 

 structures which, though never described except in my papers, 

 have sometimes been referred to as otocysts^). They show no 

 structure in any way suggestive of an otocystic nature, but are clearly 

 glandular. 



On each side, on the ventral surface of the ganglion of the chain 

 form of Cyclosalpa pinnata, there is a discoidal chamber whose walls 

 consist of a single layer of cubical epithelium supported by a basement 

 membrane of unusual thickness (Fig. 67). I have called these cham- 

 bers the ventro-lateral chambers of the neural gland. Each connects 

 with the pharynx or cloaca 2) by means of a greatly coiled tube whose 

 wall, like that of the lateral chamber, consists of an endothelium of 

 cubical cells supported by a thick basement membrane (Figs. 67—69). 

 The distal opening of these ducts is a mere pore showing no 

 enlargement and no cilia. The evidence of the glandular nature of 

 the ventro-lateral chambers will be given later in connection with the 

 description of Salpa africana-maxima. 



Near the ventro-lateral chamber of the gland lie two pairs of 

 ventro-lateral cellular outgrowths from the ganglion (Figs. 67, 68 and 

 71). Of these, one pair contains small cells like the usual small cells 

 of the ganglion, while the other pair are composed of larger cells 

 like those that lie in the ganglion, in the zone of origin of the nerves. 

 All four of these masses of cells arise in the ontogeny as outgrowths 

 from the ganglion. In the adult they are connected with the brain 

 by nerve fibres. They may be called the large-celled and small-celled 

 ventro-lateral ganglia. The small-celled ventro-lateral ganglia lie upon 

 the basement membrane of the ventro-lateral chambers of the gland 

 (Figs. 67—69 and 71), the large-celled ganglia lying above and in 

 front of the small-celled ganglia and not touching the ventro-lateral 

 chambers. Careful study has shown no interruption of the basement 

 membrane of the chambers, either where the small-celled ganglia lie 

 upon it, or at any other point. This, of course, renders doubtful, 



1) Cf. Herdman, 1888, and Goppert, 1893. 



2) In the Salpas the whole of the wall separating pharynx and 

 cloaca, except the dorsal raphe, has degenerated, so that it is not 

 possible to tell into which region these ducts open. 



