510 MAYNARD M. METCALF, 



distant from the surface of the ganglion. Close observation of the 

 cells filling the central spaces shows them to be in all stages of 

 disintegration, either the nucleus or cell body or both being ir- 

 regular. 



In the raphe we find a large, richly gangliated nerve (Fig. 15 r.n) 

 which follows the rapheal muscle nearly to its insertion at the edge 

 of the oesophageal aperture. We also see the rapheal duct {r.d). 

 This arises from near the posterior end of the neural gland and turns 

 down around the right side of the ganglion to enter the raphe. The 

 rapheal duct is larger than the gland itself and in the whole upper 

 half of the raphe it is greatly swollen, containing great masses of 

 cells degenerating to form the secretion. These degenerating cells 

 are formed from the posterior wall of the duct, while the anterior 

 wall, corresponding to and continuous with the ventral wall of the 

 neural gland proper, is composed of a single layer of cubical cells. 

 The mass of glandular tissue contained in the raphe is several times 

 greater than that in the whole epineural portion (the gland proper). 



Corresponding to the dextral asymmetry in the upper end of the 

 rapheal duct we find a similar asymmetry in the anterior part of the 

 duct of the gland. That is, the connection between the gland and 

 the ciliated funnel is established by means of a duct which runs around 

 the right side of the ganglion just behind the point of origin of the 

 anterior siphonal nerves. 



There is one further point of interest. The ganglion and gland 

 are partially fused in this species as in many others. At about the 

 the middle of the epineural gland there is an elongated area where 

 the basement membrane of its ventral wall is wanting, and the cells 

 of the ganglion so grade ofi' into those of the gland that the two 

 cannot be distinguished (Fig. 15 f). If we regard all the cells in 

 this region as belonging to the ganglion we may say that the latter 

 at this point is in direct contact with the lumen of the gland. 



Cynthia pyrifortnis Rathke. 

 Cynthia pyriformis corresponds to Cynthia papulosa in the features 

 mentioned in the description of the latter species. The ganglion is, 

 however, a little less slender and elongated. The gland also is shorter 

 and stockier. The rapheal duct and nerve are as in Cynthia papu- 

 losa. Since the gland is shorter than the ganglion, both its anterior 

 duct to the ciliated funnel, and its posterior connection with the 

 rapheal duct, are about one-third of the way from the anterior and 



