1904.] MAniXE FAUNA OF ZAXZIBAE. 291 



nioi'e clearly marked, and on (setigerous) segments three and four 

 entirely displace the brown pigment, thus forming a very con- 

 spicuous collar. An irregular, broad, longitudinal band extends 

 from the base of the median tentacle to the posterior border of 

 the first setigerous segment. The tentacles, nuchal and dorsal 

 cirri, feet, and venti-al surface are white or nearly so. 



The Chuaka specimens were described in my notes as having a 

 colour resembling that of cocoa, with small irregular marks of a 

 yellowish white. The tentacles are banded with white, and the 

 feet &c. are whitish as above. 



The above contrast more or less markedly with the appeaiance 

 of the single smaller specimen from Prison Island. This had a 

 dark red-brown gi-ound- colour, approaching that of chocolate, 

 which throws up vividly the white spots, which are here somewhat 

 larger and more definite in oiitline than in most specimens, and 

 the collar, which occupies segment five. The parapodia and their 

 appendages, the tentacles and the edges of the palps are yellowish 

 white. Gills bright red as usual. A white mai'k encircles the 

 base of the middle tentacle and thence extends to the back of the 

 prostomiurn. 



According to Peters, the original example of the species, like 

 those examined by Ehlers, was devoid of markings. 



So far, then, from the collar being a principal distinction of this 

 species, it is more often absent than present*. 



In all cases the colour dies out posteriorly or is retained only in 

 the intersegmental grooves. 



In the Maldive specimens the pigmentation cannot be certainly 

 made out. A fragment of a specimen of this species has been 

 observed to emit a strong blue phosphorescence at night. 



The general appearance and proportions of the body, which are 

 very approximately constant and fairly characteristic of the species, 

 have not yet been described in detail. The nearly cylindrical 

 anterior end is but slightly narrower than the broadest part of the 

 anterior half of the body, the position of which is from about the 

 eighth to the twelfth setigerous segments f. Further back still, 

 near its middle, the body expands again, becoming slightly broader 

 yet (see text-fig. 43, p. 292, and its explanation). 



The segments immediately following the buccal are not markedly 

 longer than those composing the rest of the anterior third of 

 the body (PI. XX. figs. 1 & 2). The first four or five parapodia 

 are rather ventrally placed, so that a narrow, flat surface is 

 enclosed between them, and the body is strongly arched dorsally 

 (see side view of anterior end, PI. XX. fig. 2) at about the twelfth 

 segment, the parapodia are completely lateral, and the ventral 

 surface becomes more, the dorsal less arched. Further back still 

 both surfaces become nearly flat, the body sometimes being quite 



* It is often absent also in Lysidice coJlaris, as noted above, arid in Eunice 

 fasciata. Ehlers, Nachr. zu Gott. 1897. 



t In all cases " sefujernns segment" is meant, a method of reckoning free from 

 ambignitv. 



19* 



