520 MAYNARD M. METCALF, 



the dorsal surface of the ganglion. It soon bends down on the right 

 side to reach the ventral surface (Fig. 29 r.d). It can be traced as 

 far as the origin of the rapheal nerve, where its cells merge into the 

 ganglion cells of the nerve. 



In the interior of the gland are found great masses of cells many 

 of which are disintegrating. In the funnel of some of my specimens 

 I find some of these cells. In many other species I have found a 

 slight amount of granular secretion in which the cilia of the funnel 

 are caught, usually, however, the funnel is empty. 



Molgula arenosa (?). 

 Plate 36, Figs. 31 and 32. 



My specimens of this species were obtained from the Naples 

 Zoological Station, labelled with this specific name. Herdman does 

 not recognize the species, nor have I found any description of it. 

 The specimens I have agree well with Verrill's figure and description 

 of Molgula arenata Stimpson, and I presume it is this species. I 

 describe it, however, under the name by which I received it from 

 Naples 1). The gland of this Molgula is much smaller than that of 

 Molgula manhattensis. It lies to the right of the ganglion rather 

 than on its dorsal surface. The ganglion is somewhat flattened dorso- 

 ventrally (cf. Figs. 31 and 32). 



The condition of the rapheal organs is the same as in Molgula 

 manhattensis^ except for the huge size of the rapheal nerve cord due to 

 the immense number of ganglion cells which accompany its fibres (cf. 

 Fig. 32 r.n). The rapheal nerve cord is larger than either of the 

 posterior siphonal nerves (cf. Fig. 31). 



Mugyra pilulavis Verrill. 

 Plate 36, Figs. 33—35. 



Here, as in the Molgulas, we find a richly gangliated rapheal 

 nerve with irregular slight enlargements hardly worthy of the name 

 of ganglia. No rapheal duct is seen, though there is a barely dis- 

 cernable backward prolongation of the duct of the gland just below the 

 point of origin of the rapheal nerve (Fig. 32). This is probably a rudiment 

 of the rapheal duct. The gland is neither dorsal to the ganglion, as 



1) Most of the European specimens I have studied were obtained 

 through the Naples Station whose assistance in this regard has been 

 of the greatest value. 



