EUSYLLIS TUBIFEX. 173 



distal piece of the bristle simple. A re-investigation may clear np doubts, especially as 

 to the fusion of the palpi at the base. 



The Trypanosyllis Bichardi of Gravier 1 (1900) from the Red Sea comes very near 

 this form, the chief distinction being the greater length of the dorsal cirri. The variation 

 in this respect may be greater than is at present supposed. 



The small size of the head of the bud in Trypanosyllis and its absence in Syllis 

 sjpongicola inclines Calvin Mensch 2 to Huxley's view that the stolon amongst Syllids is not 

 so distinctly individualized as would appear from the earlier observations of Alex. 

 Agassiz on Autolytus comutus. 



Genus LI. — Eusyllis, Malmgren, 1867. 



Head with a ciliated collar; palpi soldered at the base; general structure as in 

 Syllis. Proboscis in extrusion armed with a single conical tooth, with a double row of 

 papillas (circa ten) incomplete on the dorsal margin. Compound bristles falcate ; terminal 

 pieces short and bifid. Dorsal cirri short and indistinctly articulated. Ventral cirrus 

 broadly lanceolate. Median and posterior segments with or without long capillary 

 (swimming) bristles. Two anal cirri. 



Reprodmtim.— Epigamy occurs in this genus (Malaquin), and the genital glands are 

 developed immediately behind the proventriculus, viz. from the twelfth to the fifteenth 

 segment. The development of the swimming-bristles takes place as in schizogamy. 



1. Eusyllis tubifex, Gosse (1855). Plate LIX, figs. 11 and 13— head; Plate LXX, fig. 9 



—foot; Plate LXXIX, ^g. 1— bristle. 



Specific Characters.— Read somewhat ovoid, with a pair of comparatively small red 

 eyes on each side, the anterior and larger being the wider apart. Palpi of considerable 

 length, ovoid, soldered at the base, richly ciliated internally, and with palpocils in front. 

 Median tentacle longer than the lateral. The base of these organs is comparatively 

 smooth, whilst the distal region is moniliform. Body of about fifty-six segments, and five 

 eighths of an inch in length. Pale and translucent anteriorly, the proboscis having a bluish- 

 white iridescence and a brown speck or two. Proventriculus is opaque-white, and dotted. 3 

 Behind the latter is a pale region of the body, then the intestine gives it a pale- 

 brown hue, which increases in depth towards the tail which has its tip pale. A series of 

 white grains is grouped on the dorsum from the proventriculus backward. The tail has 

 a median lanceolate process and two long moniliform cirri with palpocils. Cirri of the 

 first four segments longest and most distinctly moniliform, the latter character diminishing 

 posteriorly. Proboscis has a denticulated edge and a single large pyramidal tooth. Foot 



1 'Xouv. Arch. Mus./ 4 e ser., t. ii, p. 168, pi. ix, figs. 12 and 13. 



2 ' Amer. Naturalist/ vol. xxxiv, p. 165 (1900). 



3 Haswell, Eisig, and De St. Joseph demur to these being termed glands. 



