418 A. M Verrill — Marine Nemertecms of New Knghnid, etc. 



Body very contractile, in extension elongated, slender, tapering, 

 and often attenuated toward the posterior end, rounded or slightly 

 depressed anteriorly, generally somewhat l)roader and more depressed 

 in the middle region, but without the conspicuous flattening back of 

 the oesophageal region seen in Cerehratidus. No anal papilla. Head 

 elongated, not very distinctly defined ; often a little wider than the 

 neck, but not constantlj^ so. Lateral slits elongated and deep, run- 

 ning close to the terminal proboscis-jiore, but usually not joining it. 

 Mouth, in ordinary states, rounded or elliptical and not very large, 

 but capable of great extension when feeding. Ocelli small, usually 

 arranged in a simple row along the lateral margins of the head, 

 sometimes absent. 



The several European species of this genus have been referred by 

 authors to a great number of different genera, of which I have indi- 

 cated only a part. The first three names cited in the synonymy were 

 all given to the same species [L. mariuvs =z L. lom/issimns) of 

 Europe and are, thei'efore, exact equivalents. The two later names 

 should, thei'efore, have been dro'pped entirely from the nomenclature 

 of the group. Unfortunately several different writers have tried to 

 restrict both Borlasia and Nemertes to groups entirely different 

 from that to wdiich they were originally given, and have thus intro- 

 duced great confusion. Each attempt of this kind has, hitherto, 

 been a failure for in most instances the new groups thus named have 

 been found to have had other and earlier names. One of the latest 

 reapplications of Nemertes to a newly constituted group was by 

 Mcintosh (Nemerteans, p. IVC). He applied it to a genus of 

 Enophi^ in a wholly new sense, Nemertes of Mcintosh, 1879, is, 

 however, antedated by Nemertes of White, 1860, applied to a Crus- 

 tacean, and therefore it could not be retained, even if the nemertean 

 genus, so named, had not already received other names. 



The use of Borlasia by Mcintosh, in a wholly new sense, seems 

 also to be untenable. 



LineUS Viridis (Fabr.) .Tolmston. 



Planaria viridis 0. Fabrichis in O. F. Miiller, Zoo]. Dan. Prod., 2r.S4, 1776; 0. 



Fabricius, Fauna Groonlandiea, p. .■'.24, 1780; Miiller, Zoologia Dauioa, ii, p. 35, 



pi. 68, figs. 1 to 4, (from Greenland specimens sent by Fabricius to Miilter). 

 Planaria, Gesserensis Miiller, Zoiil. Danica, ii, p. 32, pi. 64, fios. 5 to 8, 1788. 

 Nrin'-rtcs oUvarea ^ohwsion, Mag. of Zool. and Botany, vol. i, p. .')36, pi. 18, fig. 1, 



1837; Diesing, Syst. Helm., i, p. 273, IS.'iO. 

 Nemertes dbscura Desor, Boston Journal of Natural History, vol. vi, pp. 1 to 12. 



plates 1 and 2, 1848 (embryology). 



