138 WESLEY R. COE. 



groups of sensory cells imbedded in the integument. The cells 

 are provided with slender distal processes and each group is sup- 

 plied with a nerve leading to the brain or to the lateral nerve, ac- 

 cording to its location (Fig. nA}. It is not improbable that such 

 integumentary sense-organs occur in the majority of the pelagic 

 species, but that the loss of the integument during capture has 

 prevented their discovery. 



SUMMARY. 



Correlated with their usually gelatinous consistency, weak mus- 

 culature and other adaptations for life far beneath the surface of 

 the oceans, the nervous system of the bathypelagic nemerteans 

 (Pelagica) differs considerably from that found in the littoral and 

 bottom-living relatives (Reptantia). Comparisons are made be- 

 tween the Pelagica and Reptantia with respect to each of the prin- 

 cipal parts of the nervous system. The special sense-organs of 

 the Reptantia are either lacking entirely or merely vestigial in the 

 bathypelagic forms. With particular reference to a recently 

 described species, Neuronemertes aurantiaca: 



1. The dorsal nerve is not connected directly with the brain. 



2. The dorsal nerve is provided with metameric ganglia, not 

 previously known for any nemertean. 



3. A pair of dorsolateral nerves connects both with the dorsal 

 nerve and with dorsal peripheral branches of the lateral nerve 

 cords. 



4. A delicate intermuscular plexus lies between the two body 

 musculatures. 



BIBLIOGRAPHY. 



Brinkmann, August. 

 '17 Die pelagische Nemertinen (monographisch dargestellt). Bergens 



museums skrifte, ny rsekke, 3, 8, 194 pp., 16 pis. 

 Burger, Otto. 



'09 Die Nemertinen. Wiss. ergebn. deutsch. tiefsee-exp. Valdivia, 1898- 



99, 17, 171-221, pi. 24-36. 

 Coe, W. R. 

 '26 The Pelagic nemerteans. Mem. Mus. Comp. Zool. Harvard Coll. 



49, 245 pp. 31 pis. 

 Stiasny-Wijnhoff, Gerarda. 



'23 On Brinkmann's System of the Nemertea cnopla and Sibogancmertes 

 wcberi, n.g., n. sp. Quart. Journ. Micr. Sci., 67, 627-669. 



