■296 bulletin: museum of comparative zoology. 



pylorus extends about as far posteriorly beyond the most anterior 

 sexual glands as the distance between these and the brain. In other 

 words, the sexual glands extend forward through half the distance 

 between the brain and the opening of pylorus into intestine. 



Nephridia. — Nephridial canals are of large size and' are situated 

 both above and below the lateral nerves immediately posterior to 

 the brain region. A single pan* of large efferent ducts opens to the 

 ventro-lateral sui'faces of body a little posterior to the middle of the 

 very short nephridial region. 



Cerebral sense organs remarkably voluminous, extending from in 

 front of brain back beneath the ventral ganglia nearly to the pos- 

 terior border of latter. 



Habitat. — Monterey, Pacific Grove, San Pedro, and San Diego, 

 California, on piles and among algae. Very common in all locali- 

 ties. 



Sexually mature in August and September. As in related species 

 sexual glands reach well forward toward the head, and are densely 

 packed throughout remainder of body. Mature ova are large ; pale 

 i"ose in color. 



80. Tetrastemma bilineatum C'oe. 



Harriman Alaska Expedition, 11, p. 164, PI. 14, fig. 6; PI. 21, figs. 



13, 14; PL 22, fig. 4, 1904. 



PI. 1, fig. 10 ; PI. 2, fig. 25. 



This species, which is abundant on piles of wharves in San Diego 

 Harbor, California, may be recognized l)y the following characters : 



Body rounded throughout, moderately slender, of minute size, 

 measuring only 5-10 mm. in length and less than 1 mm. in diame- 

 ter; head provided with two paii's of faintly marked oblique grooves. 



Color. — General color of body fiesh color, creamy, or grayish, 

 with two very conspicuous sharply marked brown, reddish brown 

 or chocolate brown stripes extending nearly the whole length of 

 dorsal surface (PI. 1, fig. 10 ; PI. 2, fig. 25) ; ventral surface gray- 

 ish. Stripes terminate anteriorly between or somewhat in front of 

 anterior ocelli, or sometimes reach to tip of snout. Diameter of 

 each stripe perhaps one sixth the diameter of body, the two stripes 

 being separated by about twice the diameter of each. Stiipes retain 

 deep brown color even after imbedding in paraffin. 



