2 THÜS. H. MONTGOMEEY, 



1. Zygonemertes virescens (Verr.) n, g, 



= Ämphiporus virescens Verb. (1892). 



I liave separated this species from the genus Ämphiporus and 

 placed it as the type and only known representative of a new genus, 

 Zygonemertes, on account of the following peculiarities in its Or- 

 ganisation : 



1) The rhynchocoel extends to the posterior end of the body, 

 while the thickened proboscis (with the exclusion of its retractor 

 muscle) does not extend quite half the length of the rhynchocoel 

 (Fig. 28). The basis of the central stilet (Fig. 24) is very large, 

 considerably elongated, flattened or slightly concave posteriorly; the 

 basis is constricted near its posterior end. The central stilet is 

 straight, massive, not half the length of its basis. 

 *' 2) Longitudinal nerves of the proboscis either 10 or 11 in number. 



3) A few elongated subepithelial gland cells ("Cutisdrüsen"), which 

 stain with haematoxylin, are situated in the head region. 



4) Shape of body resembling an Ämphiporus, not as elongate as 

 in Eunemertes; also contractile as in the former genus. 



5) Ocelli numerous, small, extending behind the brain on the 

 dorsal and lateral aspects of the lateral nerve chords (Figs. 14, 15). 



These five points give the diagnosis of the new genus ; the follow- 

 ing anatomical structures may also be noted: 



Sensory hairs and pigment are wanting in the body epithelium. 



The posterior commissure of the lateral nerve chords, is situated 

 at the end of the body, above the intestine. 



In the body epithehum, between its constituent cells, He peculiar, 

 curved bodies (Fig. 23), larger at one end than at the other, refrac- 

 tive, hard, brittle, of a yellowish-green color, and which do not stain 

 with the reagents used, They have a close resemblance to the bodies 

 found in Eunemertes echinoderma (Marion), from which they difler 

 only slightly in form ; they are always present, and being easily re- 

 cognized with low powers of the microscope, present a good charac- 

 teristic for determining the species. I conclude that these peculiar 

 bodies are of extraneous origin, since there are no special cells in 

 the epithelium for producing them, nor do they present dififerences in 

 dimensions and form — differences which we would expect to find, 

 were they developed within the epithelium. 



The central stilet of the proboscis has been already noticed; 



