1903.] MARINE FAUNA OP ZANZIBAR. 135 



Thus, though in the majority of cases the disappearance of 

 hooked setfe and the change in the character of the venti-al 

 cuTus are coincident with the appeai'ance of the first gill, excep- 

 tions are proportionately numerous, so that variations of these 

 characters cannot well be made the ground for systematic 

 distinctions. 



Genus Onuphis. 



Onuphis holobranchiata Marenzeller. (Plate XIV. fig. 2.) 



Five specimens were collected, and in all the hind end was 

 missing. The largest fi-agment is very nearly of the same size as 

 that described by Marenzeller from Japan, viz. 4 cm. x 0"3 cm., 

 and consists of nearly the same number of segments, 8-5. This, 

 with three others about half the size, was dredged from 10 fathoms 

 in Wasin Harbour ; the fifth, still smallei', being from the shore 

 in the same locality. This last specimen is abnoi'mal in having 

 no gills on the first two pairs of feet. 



The coloration of the living animal is characteristic, the 

 pattern on its dorsal surface serving to distinguish it at a glance 

 from any of the numerous small species of Einiicidfe living 

 in the same locality. The ground-colours are of a light flesh-tint 

 ventrally and light yellow-brown dorsally, but the central part 

 of the prostomium and a small I'ound area in the middle of 

 each segment are white. The upper surface, however, as far as 

 the thirty-fifth segment, is largely covered by markings of a dark, 

 rather pui^ple - brown (Marenzeller's " Dunkelbraun - violett " 

 suggests an almost blue colour, which is not that present in my 

 specimens). These are most numerous and closely placed at the 

 bases of the feet, with the exception of the first three. On either 

 side of the white central marks are slender transverse lines, three 

 paii's, one of long, two of short marks to each segment. To the naked 

 eye the back appears mai-ked by two pairs of longitudinal bands, 

 the outermost darker and of definite zigzag shape, the inner 

 which bound the median moniliform white stripe, lighter and less 

 definite in outline. The former is omitted fi'om the first four 

 segments, and the latter also is irregular there. There are dark 

 marks on the prostomium just behind the bases of the tentacles, 

 the ringed portions of which are themselves lightly marked. The 

 fig. 2, PI. XIV., shows this pigmentation, the peculiar proportionate 

 lengths of the tentacles, &c. 



In feet, setfe, gills, and othei- chai'actei's my specimens agree 

 minutely with Marenzeller's. The former, like their gills, are 

 white and somewhat dorsally directed. The mandibular plates 

 difier slightly in shape from Marenzeller's figure, having, in the 

 cutting-edge, one deep, instead of two shallow notches. 



EUNICIN^, 



Cxenus Marphysa. 

 The following table, which includes all the species of which 



