NEMERTEANS 177 



Nervous System and Sense Organs. Brain and lateral cords as 

 in related species. Cephalic and buccal nerves large. 



Cerebral sense organs highly specialized, and of rather large size. 

 They are much elongated, and their anterior ends are situated laterally 

 in the angle between the dorsal and ventral ganglia. After extending 

 back nearly to the posterior end of the dorsal ganglion, each sense 

 organ enlarges until it is nearly equal in diameter to the dorsal gang- 

 lion, and eventually fuses completely with the posterior surface of the 

 latter. At the narrow, anterior end of each sense organ a ciliated 

 canal leads outward to open into the rather conspicuous oblique 

 cephalic furrows. 



Reproductive Organs. Sexual products were found to be mature 

 in the specimens dredged off San Pedro in August, but those examined 

 at Monterey in September had neither ripe eggs nor sperm, and had 

 evidently recently discharged their sexual products. The mature eggs 

 are large and opaque, and when brought into sea water surround them- 

 selves with a jelly-like coating. 



Habitat. Dredged among red algae, of color closely approxi- 

 mating that of the worms, in 50 fms., between San Pedro and Santa 

 Catalina Island, Calif. This is a common species in that locality, and 

 the individuals are remarkably hardy, living for a day or more among 

 damp seaweeds. A number of large living specimens were obtained 

 from Chinese fishermen, who caught them on their hooks in rather 

 deep water (perhaps 10-20 fms.) in Monterey Bay, Calif. Just how 

 the worms come to be caught on these hooks, which are set for ' rock- 

 cod,' is difficult to imagine, unless they crawl about among the sea- 

 weeds on the bottom, and, as the hooks drag through, are caught in 

 their bodies. It is possible that the worms actually find the bait and 

 cling to it. The fact that the body is often entirely without injury 

 points to this conclusion. The fishermen offered no conclusive evi- 

 dence in the matter. The species must be abundant, or it would be 

 more rarely caught on hooks. 



Individuals live for a long time in captivity, and do not break up 

 when roughly handled. They may be easily preserved without rup- 

 ture, or without excessive contraction if killed slowly. Natural colors 

 are well retained in formalin, but fade in alcohol. 



16. ZYGEUPOLIA LITTORALIS C. B. Thompson 



Zool. Anz., xxin, p. 151, 1900. 



Proc. Acad. Nat. Sci. Philadelphia, 1901, p. 657-739, pi. XL-XLIV, 1902. 



This very interesting species which has been so carefully studied 

 and fully described by Miss Thompson (1902) occurs rather commonly 



