NEMERTEANS 157 



color. This white color also covers the whole ventral side of the 

 head, as is shown in p1. xiv, fig. 10. 



After preservation, and even after imbedding in paraffin, the dark 

 brown color of body and the white anterior portions with the peculiar 

 cep halic marking remain almost as distinct as in life. 



Blood vessels are distinguished easily because of their reddish color. 

 This color is resident in the oval or rounded discoid corpuscles, as in 

 several other species of the genus. The corpuscles are very flat, with 

 several small pigment bodies in each. 



Ocelli. — The four ocelli are of rather large size, and arranged 

 nearly in the form of a square (text fig. 20). They lie deep in the 

 tissues of the head, and occupy a variable position as regards the mark- 

 ing on the head, but in ordinarj- states of contraction the posterior pair 

 lies just behind the basal portion of the marking, while the anterior 

 pair is situated beneath the antero-lateral portions of the wreath, as 

 indicated in p1. xiv, figs. 9— 11. As seen in sections, the eyes lie deep 

 in the midst of the cephalic tissues. 



Size, — Length about 15—25 mm. ; width commonly less than i mm. 



Proboscis. — Of moderate size ; whitish or pale flesh color. Mus- 

 cular and other layers as in related species. There are ten proboscidial 

 nen'es. Central stylet slender, acutely pointed; basis conical, opaque 

 and granular in posterior third (pi. xxi, figs. 10-12). 



Body Walls. — Composed of the usual layers. The pigment which 

 gives the body its color is found in a thin, but very dense, layer be- 

 tween the integument and the basement layer, and to a less degree 

 among the bases of the epithelial cells of the integument. It is even 

 more dense in the cephalic marking than elsewhere. Nearly the whole 

 space enclosed by the body walls is occupied by the internal organs, so 

 that there is but very little body parenchyma. 



Submuscular glands are almost entirely wanting. Cephalic glands 

 are but little developed. Practically the only glands, therefore, which 

 open at the surface of the body are the integumental glands. It was 

 noticed in life that the worms of this species were remarkably free from 

 mucus. There are numerous forms in which an abundance of mucus 

 is associated with an unusual development of the submuscular glands 

 (in Carcinonemertes epialii, for example), so that it seems probable 

 that these glands furnish a supply of mucus accessory to that of the 

 integument. 



Alimentary Canal. — A pair of very slender intestinal caeca extend 

 forward to abut against the posterior faces of the dorsal brain lobes. 

 For a considerable distance behind their anterior ends these caeca are 



