COE: NEMERTEANS OF WEST AND NORTHWEST COASTS. 1 K^ 



chocoel vessels is present, but these are small in size, and do not 

 extend far posteriorly. 



Neplxridia. — The nephridial canals are even shorter than in most 

 related species, but show unusually well developed "nephridial 

 glands " in the lateral walls of the lateral blood lacunae. The 

 single pair of nephridiopores lie at the posterior ends of the canals 

 and are situated on the dorso-lateral margins, as indicated in figure 

 91, PI. 15. The efferent ducts are sometimes enormously swollen 

 when passing through the circu^lar muscles and basement membrane. 

 From the efferent ducts a large convoluted canal passes forward for 

 some distance without diverticula. It eventually turns backward 

 and gives off several branches which subdivide to form the 

 " nephridial gland." The main canal lies dorsally to the lateral 

 blood vessel, and well separated from it. The nephridial gland is 

 made up of a mass of minute tubules lined with a flattened epithe- 

 lium and projecting slightly into the lumen of the lateral blood 

 lacuna along its lateral border (PI. 15, fig. 92) . The general 

 structure is very similar to that found in Carinoma and Carinina, 

 The larger nephridial canals and the efferent ducts are lined with 

 columnar ciliated cells as in other species. The nephridiopores are 

 situated very near the anterior end of the lateral sense organs (PI. 

 15, fig. 91), so that it is only in a very few sections that both the 

 nephridial canal and sense organs both appear. 



Nervous system.— The brain lobes, dorsal median neiwe, buccal 

 neiwes, and proboscis nerves are as in other species of the genus. 

 The latter come off very abniptly from the internal border of the 

 ventral ganglia, as Biirger ('95, PI. 11, fig. 3) figures for C.poly- 

 morpha. 



Sense organs. — The cerebral sense organs are well developed. 

 They consist of a |)air of sharjily demarcated pits reaching inward 

 to the basal layer of the epithelium (PI. 15, fig. 90), and are situ- 

 ated just opposite the posterior ends of the dorsal brain lobes. The 

 pits are lined with small, slender, ciliated cells, and are innervated 

 by fibers passing from the posterior ends of the dorsal brain lobes, 

 from which they are separated by the thin basement membrane 

 only. Just dorsal to the sensory pits lies a pair of oblique, shallow, 

 lateral grooves, the epitheUum of which is clearly distinguished from 

 that of the surrounding parts by being very much thinner and lack- 

 ing the thick mass of gland cells. These lateral grooves are wholly 



