Notes on the morphology of the Tunicata. 497 



more ciliated funnels, likewise, are found in every Tunicate, though in 

 some forms, e. g. the Salpas, the funnel has no connection with the 

 gland. In the raphe, in addition to a large blood sinus running its 

 whole length, and a strong muscle attached below near the oesophagus 

 and above united to the muscles around the ganglion, there is found 

 a nerve which is gangliated, and, in many genera, in addition a tube 

 is seen which is continuous above with the duct of the gland. In 

 some species functional gland cells are associated with this tube. In 

 this section of this paper, I invite attention to the comparative ana- 

 tomy of these organs in 54 species representing all but two of the 

 families and all but two of the sub-families^) of the whole group 

 Tunicata. These families are the Polystyelidae and the Coelo- 

 cormidae, the latter containing only one species described by Herd- 

 man from the South Atlantic ocean. The sub-families not represented 

 are the Corellinae and the Hijpobythiinae, both being sub-divisions of 

 the Ascidiidae. The last sub-family contains but two species found at 

 great depth in the Atlantic and Pacific oceans. I hope some one 

 having the necessary material may be sufficiently interested to study 

 the conditions of the gland in these forms and compare with my results. 

 It is natural to begin the description with the Simple Ascidians. 

 Ciona intestinalis will serve well as a type form with which other 

 species may be compared. 



Ciona intestinalis L. 2). 



Plate 34, Figs. 1, 2 and 3. 

 The ganglion and gland seen in dorsal view present the appear- 

 ance sketched in Fig. 1. The ganglion {gg) is oval, twice as long as 

 broad, and bifurcated at either end where the great siphonal nerves 

 arise. The right posterior nerve is much larger than its fellow of 

 the other side, and from its base is given off a branch, not shown in 

 the figure, which runs ventrally into the raphe. (Cf. Fig. 3 r.w, a 

 parasagittal section slightly on the right side of the median plane.) 

 This is the rapheal nerve. It follows the course of the large rapheal 

 muscle nearly to the oesophageal opening, its fibrils apparently being 

 distributed, at least in part, to the fibres of the muscle^). A few 



1) Heebman's classification is followed in the main. Cf. Herd- 

 man, 1891. 



2) The best description yet published of the ganglion and neural 

 gland in this species is that of Roule. Cf. Roule, 1886. 



3) This muscle is not shown in the figure. 



33* 



