112 bulletin: museum of comparative zoology. 



such rings, although many are interrupted on ventral surface, and 

 many others consist of very fine double lines. ^ 



In one individual collected at Monterey the white rings in the 

 middle portions of the body were practically as wide as the brown 

 surfaces between them, so that the general color effect in this por- 

 tion of the body was grayish instead of the usual brown color. 



The worms live in thin, but tough, translucent tubes, which they 

 secrete about their bodies. Such tubes are open at both ends, 

 and are often secreted w^hen the worms are kept alive in an 

 aquarium. 



To the anatomical descriptions already published (Coe, :01;, the 

 follo^\^ng additional peculiarities of internal structures, based on the 

 study of several additional series of sections, prepared by Mr. 

 Griffin, may be given. 



Body vxills. — Epithelium of body very thick, -wdth closely packed 

 deep seated glands. The two circular muscular layers of the body 

 wall are without crossings, except in a limited area in, and immedi- 

 ately posterior to, the nephridial region. In this area the dorsal 

 crossings are quite conspicuous, but the ventral are but faintly indi- 

 cated. The internal circular muscular layer reaches a considerable 

 thickness in the anterior nephridial region (PI. 15, fig. 92), but 

 diminishes in front of the nephridiopores. In the region of the 

 nephridiopores the longitudinal musculature is partially split up into 

 a thick outer laver and a thin inner layer lying immediately exter- 

 nal to the circular muscles about the eso])hagus. These two layers 

 are separated laterally, and to some extent ventrally, by the gelat- 

 inous tissue of the body cavity (PI. 15, fig. 92) . A band of longi- 

 tudinal muscles lies between esophagus and proboscis sheath in 

 nephridial region. The proboscis remains attached to its sheath 

 for a very short distance behind the brain region. 



Cephalic glands are absent among the tissues of the head. There 

 is a A-ery thick layer of deeply staining glands, however, about the 

 rhynchodaeum, but these disappear completely in the brain region. 



Blood vascidar system. — The paired lacunae in the head are 

 large, and reach nearly to anterior extremity. They are much dis- 

 sected, even as far back as the mouth, by fibrous strands (PI. 15, 

 fig. 90) which cross them in all directions. The ventral anastomosis 

 near the mouth region is an unusually large lacuna. A pair of I'hyn- 



1 For details see Coe, :01, p. 15. 



