1904.] ON TWk MARINE FAUXA OF ZANZIBAR. 287 



4. The Marine Fauna o£ Zanzibar and British East Africa, 

 from Collections made by Cyril Crossland in the Years 

 1901 and 1902.— The Polychteta. Part III.* With 

 which is incorporated the Account of Stanley Gardiner's 

 Collection made in the Maldive Archipelaoo in the 

 Year 1899. By Cyeil Ceossland, B.A., B.Sc, F.Z.S., 

 the Gatty Laboratory, St. Andrews, 



[Eeceived December 15, 1903.] 



(Plates XX.-XXII.t and Text-figures 43-66.) 



Genus Eunice. 



The species fall into the following gi-oups, of which A contains 

 the greater part of the genus : — 



A. Generalised species with tentacles of moderate 



lengtli, jaws of normal foi-m and constitution, 

 gills well developed in tlie adult, and seta; of the 

 usual kinds. 

 a. Gills continue to hind end of the body. 



1. Gills begin about feet 3 to 8, complex but 



small in proportion to size of body. 



a. Quadripartite prostomium, gills of up to 



30 filaments, and characteristic setae ... J?. apJirodiiols, p. 288. 



h. Bilid prostomium, gills of about 8 fila- 

 ments, and seta3 of quite general form . iE. gruhei, p. 288. 



2. Gills begin between feet 15 and 20, attain 



to from 4 to 10 filaments anteriorly but 

 are simpler posteriorly. Setie of general 



form JE:. fl/r«, p. 289. 



j8. Gills occur only on the anterior third of the bodj^. 

 1. Begin about 6th to 9th feet. Body- 

 form characteristic JE. coccinea, p. 297. 



B. li'orming tubes of characteristic structure and 



material. Otherwise very like members of 

 group A. 



1. Compound setae with sword-shaped articulated 



pieces anteriorly, sickle-shaped posteriorly ... ]S. hihifex, p. 303. 



2. All compound setse of the latter form IS. flnridana & J'7. tih iana, 



IS. conglomerans ^ & IS. guniieri (= awpJiifieUce, &c.). 

 (These are the remaining species of the group.) 



C. With long tentacles, large gills beginning before 



the 10th foot, three-hooked acicular seta;, and 

 markedly asymmetrical jaws. 

 a. Head neai-lj'^ as broad as the rest of the body, 



tentacles deeply annulated, jaws strong 



and chitinous. 



1. Gills confined to anterior part of the 



body..... E. murrai/i, p. 310. 



2. Gills continued to near anus IS. antentlata, i^. 312. 



* For Part I., see P. Z. S. 1903, vol. i. p. 169 ; Part II., 1903, vol. ii. p. 129. 



t For explanation of the Plates, see p. 330. 



X It is not suggested that this grouping is necessarily of more than temporary 

 utility, but it is certain that in a natural system the larger groups cannot be 

 separated by one character alone, as has hitherto been attempted. Reasons for 

 laying less emphasis upon characters employed for the major divisions b.y earlier 

 workers are given among the notes on variation of the species described below. 



§ These three species are from Ehlers' ' Florida Anneliden,' 1887. E. con- 

 fflomerans is very near to ^. tubifex, and is distinguished from all other Eunicids 

 by its compound seta;. 



