410 STHENELAIS BOA. 



head is fixed inferiorly to the massive bases of the tentacular cirri (first foot). Externally 

 two tapering cirri of considerable length occur, one, the longer, from the dorsal edge, and 

 another a little shorter from the ventral edge above the palpi. Behind the dorsal tentacle 

 is a T-shaped ciliated process (ctenidium). To the inner side of the ventral cirrus is a 

 sickle-shaped blunt appendage (cuilleron cephalique, or buccal ctenidium), richly ciliated 

 and continuous with a well-marked ridge on the inner surface of the basal process. On 

 the inner side of the bristle-tuft superiorly, again, is another short subulate cirrus, the 

 homologue of the lateral tentacle (Pruvot and Racovitza). The long subulate and smooth 

 palpus springs from the middle of the ventral face of the basal process, and has a scoop- 

 shaped flap (ctenidium) ensheathing it internally. The first foot carries a double series 

 of bristles directed forward and inward, and consisting of somewhat stiff, long, slender, 

 curved bristles closely spinous towards the tip. The upper series of bristles had many- 

 stalked infusoria like Bhabdostyla. 



Body four to eight inches in length ; elongate, not much tapered anteriorly, but 

 gradually diminishing posteriorly ; rounded dorsally and flattened ventrally, composed 

 of 170 to 200 or more bristled segments. The dorsal surface is marked anteriorly by 

 transverse lines, and the median region forms an elevated ridge, and sometimes has a 

 bluish-green or ochreous colour. The post-cephalic ridge has at its sides small 

 ciliated processes, which at first sight resemble parasites. The ventral surface 

 is of an iridescent flesh-colour, or bluish-green (from eggs) marked by the red 

 central vessel, and with a raised transverse line between the centres of the feet. 

 Posteriorly the body terminates in two tapering caudal styles. 1 A segmental eminence 

 occurs at the base of each foot, and on the adjoining region is a little funnel-shaped 

 papilla, but apparently unconnected with the former. In the anterior feet the funnel is 

 in the centre of the base of the foot, but it by-and-by moves forward, so that through- 

 out the rest of the body it is near the anterior edge of the foot. The funnel-shaped 

 papillse are continued from the fourth bristled feet to near the top of the tail; about 

 twenty segments, however, are devoid of them. In the males this funnel-shaped 

 organ does not appear to be present, but the segmental eminences are very prominent, 

 and have an oblique crest. In spirit the sperms sometimes form masses of a rope-like 

 character externally, as if they had issued (on immersion in spirit) from a minute pore. 

 The cuticle is considerably thickened over the nerve-area. 



The proboscis has eleven papilla on each half (dorsally and ventrally). These are 

 large and somewhat conical, slightly constricted at the base, and with a projection 

 internally about the middle. The teeth do not seem to bite alternately, as in the 

 Polynoidas, but the lower pass in front of the upper pair (Plate XXVI a, fig. 21). 



No pregastric ca3ca are present, but short intestinal caeca occur laterally. 



Scales (Plate XXXIII, fig. 16), 156 pairs, covering the entire dorsum, of a greyish 

 hue, the anterior especially showing numerous dark brown grains ; all however possess 

 them, unless when recently reproduced. Towards the posterior end they have a 

 broad band of dark grey or brownish grey along the posterior border internally, and 

 occasionally externally a dappled condition or grains of the same dark grey colour. A 



1 Body terminated by four small cirri (De Saint-Joseph). 



