RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. 63 



V. — A CONTRIBUTION TOWARDS OUR KNOWLEDGE OF THE 



POLYCHAETA OF SOUTH AFRICA. 



BY Dr. R. HORST. — (WITH 2 TEXTFIGURES). 



2. Nereidae '). 



Nereis {Plattj nereis) striata (Schm.). 



(Mastig oner eis striata Schm.). 



Of this species several specimens were collected in Table bay, where 

 they were found for the first time by Schmarda 2 ) and afterwards met 

 with by Willey 3 ). Unfortunately the description of the species is rather 

 short and incomplete and the synonimy somewhat dubious; therefore I 

 think it not superfluous to give a detailed account of them, especially 

 while an epitocous male was among them. The specimens are rather 

 small, measuring about 30 mm. in length, whereas the number of seg- 

 ments amounts to 70. The specimens of Schmarda and of Willey were 

 somewhat larger, measuring 50 mm. in length, with about 80 segments. 



Nereis striata is characterized by a conspicuous coloration, consisting 

 of a narrow, transverse, black band (dark violet in the living worm), 

 which laterally becomes broader and acquires the shape of a brace, over 

 the dorsal side of each segment; moreover there occurs a double black 

 patch at the base of the dorsal cirri and an other one near the ventral 

 cirri, whereas an interrupted black line runs in the median ventral line. 

 Armature of the proboscis : maxillary region, I absent ; II a narrow, 

 semilunar patch of paragnathi; IV a semilunar group, consisting of five 

 rows of densely crowded paragnathi; III three transverse groups, con- 

 sisting of two or three separate rows of paragnathi ; basal region : Y absent ; 

 VI a small distichous patch ; VII and VIII five, transverse, distichous 

 or tristichous acervuli. In some specimens group II of the maxillary 

 region is absent or only faintly developed. In the anterior body-region 

 (Fig. 1) the lip of the notopodium is deeply notched and consists of a 

 small, round, dorsal lobe and a large, oval, ventral part; the dorsal ligule 

 is obtusely conical, nearly as long as the dorsal lip. The dorsal cirrus, 

 emerging from the middle of the ligule, is about twice as long as it. The 

 neuropodial lobe, much shorter than the notopodial one, has obtusely conical 



1) Por part I, see Vol. Ill, p. 285 of this journal. 



2) Neue Wirbellose Thiere, II, 1861, p. 112, PI. XXXI, fig. 248. 



3) Littoral Polychaeta from the Cape of Good Hope, 1903, p. 262, PI. XIII, fig. 14, PI. XIV, 

 figs. 11 and 12. . 



