498 MEYNARD M. METCALF, 



ganglion cells are associated with the nerve at its upper end. The 

 ganglion in section shows the usual cellular cortex and fibrous cen- 

 tral area. 



The ciliated funnel is immediately in front of the ganglion and 

 a little on the right side (Fig. 1 cif). In ventral view (Fig. 2) one 

 sees that it has a form very usual for the Ascidian funnel, that of 

 a horse - shoe with its ends incurved and somewhat coiled. As is 

 frequently the case in other species, the coils are not symmetrical. 



The funnel (Fig. 3 c.f) leads back into the duct of the neural 

 gland, which is a rather narrow tube running along the ventral side 

 of the ganglion almost to its posterior end. Here it bends to the 

 right and upward, passing to the right of the base of the great right 

 posterior nerve (Fig. 1 and Fig. 3 r. d). It now bends across above 

 this nerve to reach the median plane where it turns sharply down- 

 ward into the raphe, following the rapheal nerve. The rapheal duct 

 ends blindly not far above the opening of the oesophagus. Through- 

 out its length it presents an even contour with no glandular swellings. 

 Its lumen is distinct. Its lining epithelium consists of cubical cells 

 similar to those lining the duct between the gland and the ciliated 

 funnel ^). Fig. 3 shows that the rapheal organs described lie between 

 the cloacal epithelium and the great median blood sinus of the raphe, 

 which is continuous above with the sinus in which lie the brain and 

 neural gland. 



The neural gland is an evagination from the ventral wall of the duct 

 opposite the ganglion ; the gland being ventral, the ganglion dorsal (Fig. 3). 

 To be strictly accurate the gland should be called an outgrowth from the 

 duct rather than an evagination, for, as Willet has so clearly shown for 

 this species and for Clavelina, it is formed as a thickening of the 

 ventral wall of the duct at a time when the duct is still the tube of the 

 central nervous system ^). The gland is considerably branched, the lumina 

 of the branches all uniting to open into the ventral side of the duct 

 by a great opening opposite the middle of the ganghon (Fig. 3). All 



1) Nassonoff in 1876 gave a very clear figure and description of 

 the rapheal duct in Molgula tuhulosa, and more recently (1892) Julin 

 has described the same structure in Styelopsis grossularia. I had not 

 seen these papers previous to the publication of my description of the 

 neural gland in Cynthia papulosa, or I should have acknowledged the 

 priority of the descriptions of Nassonoff and Julin. 



2) Cf. WiLLEY, 1893. I can confirm this description for Ecteinas- 

 cidia turbinata and Molgula manhattensis. 



