ALASKA NEMERTEANS 39 



and had 3 single eyes between the anterior and posterior clusters, 

 while one from Yakutat had 3 large ocelli in a row on the anterior 

 margin of the head, and a pair of scattered clusters of 8 to 12 eyes 

 each in front of the brain. When the head is contracted so that it is 

 emarginate in front, the arrangement of the eyes into clusters disap- 

 pears, and they are then all scattered irregularly on the antero-lateral 

 margins. Figs. 8 and 9 show the general arrangement of the eyes. 



Color. The whole body, both above and below, is a homogeneous, 

 very pale red or flesh-color (pi. in, figs. 3, 4), and is entirely with- 

 out markings except for a longitudinal median line of deeper red, 

 showing the position of the proboscis sheath, and the deeper color of 

 the intestinal lobes. In some specimens the reddish color was more 

 pronounced anteriorly, and some were very pale. The intestinal lobes 

 are seen through the clear tissues of the body walls as narrow, trans- 

 verse markings, slightly darker than the rest of the body. The reddish 

 color of the brain and lateral nerves is often conspicuous from the 

 dorsal surface (pi. in, fig. 3). 



Size. Individuals were seen which were 500 mm. long in greatest 

 extension, although the majority were less than half this length. 



Proboscis. Mouth and proboscis open together through a subter- 

 minal pore. The proboscis is large (pi. vin, fig. 7) and of moderate 

 length. The short proboscis sheath does not reach far beyond the 

 middle of the body. The armature of the proboscis shows marked 

 variations. The size and shape of the central stylet and its basis, 

 however, remain fairly constant. The central stylet is of the regular 

 Amphiporus type, is moderately slender, and rests on a moderately 

 slender basis. The basis is slightly narrower in front and is rounded 

 behind (pi. vn, fig. 4) . The number of pouches of accessory stylets 

 is commonly from 6 to 12. One specimen had 12 of these pouches, 

 each with one or two slender stylets; each of two others had six 

 pouches with two stylets in each pouch. Three specimens had each 

 twelve nerves in the proboscis, while a fourth specimen had but 

 eleven. 



Cerebral sense-organs. Unusually small and situated some distance 

 in front of brain-lobes. They occupy positions very close to the ven- 

 tro-lateral borders of the head, and beneath the cephalic blood lacunae. 



Nephridia profusely branched, and extending throughout the greater 

 portion of esophagal region, though they do not reach the brain. 

 Their numerous branches ramify both above and below the lateral 

 nerve-cords, and several efferent ducts of small size lead to the exterior 

 from both the dorsal and ventral branches. There may be about five 



