Figure 2 in the larger drawing at the right shows the nervous system as viewed from the side with the dorsal side to the left. The central core of the ganglion and cord is to indicate the position of the fiber area. The small drawings at the left show various levels of the nervous system as seen in cross section. The ventral side is up. The drawing at the top is through the brain before the commissures are reached, the next lower is through the thickest part of the brain and the lower two drawings are through one of the lateral cords. _Burger, O._ 1891 Beitrage zur kenntnis des Nervensystems der Wirbellosen. Neue Unter. über das Nervensystem der Nemertinen. Inst. a. d. Zool. Sta. Neah. 10. _Burger, O._ 1890 Beitrage zur Kenntnis des Nervensystems der Nemertinen. Zeit. Wiss. Zool. Bd. L. ---- 1895 Die Nemertinen. Fauna u. Flora d. Golfes v. Neapel. _Coe, W. R._ 1895 On the Anatomy of a Species of Nemertean (Cerebratulus). Trans. Conn. oc. ix. _Coe, W. R._ 1910 Nemerteans. Haniman Alaska Series, vol. xi. _Delage et Herouard_ 1897 Trait de zoologie concrete. Les vermidinens. Vol. v. Paris. _Haller, B._ 1889 Beitrage zur kenntnis der textur des Central-nervensystems. Heherer Wurmer. Arb. des Zoolog. Inst. Wien. T. viii, Heft. 2. _Hubrecht, A. A. W._ 1887 Relation of the Nemertea to the Vertebrata. Quart. jour. mic. Sc. XXVII. _Hubrecht, A. A. W._ 1880 Zur Anatomy und Physiology des Nervensystems der Nemertinen Nat. Ver. der k. Akad. Decl. xx. ---- 1887 Report on the Nemertia collected by H. M. S. Challenger. Rep. Sc. results H. M. S. Challenger. Zool., vol. xix. _Kemnel, J. V._ 1877 Beitrag zur Kenntnis der Nemertinen. Arb. a. d. Zool. Inst. Würzburg IV. _McIntosh, W. C._ 1874 A monograph of British annelids. Part I, Nemertineans. Ray. soc. _Montgomery, T. H., Jr._ 1897 Studies on the elements of the central nervous system of the Heteronemertini. Jour. morph., vol. xxx, No. 3. _Mosley, H. N._ 1875 On Pelagonemertes rollestoni. Ann. mag. nat. hist., vol. xv. EXPLANATION OF PLATE