Gatty Marine Lahoratory^ St. Andrews. 15 



centre of the ridges, which pass in front from the bases of 

 the setigerous papillae to the edge of the ventral scutes, and 

 behind these almost to the mid-ventral line. With the 

 cessation of the bristles a change ensues, for the hooks are 

 now borne on a prominent lamella — slightly crescentic or 

 scoop-shaped, — and placed laterally at the posterior edjic of 

 each segment, which still consists of two rings. These 

 lainellse diminish in size posteriorly, becoming minute to- 

 ward the tip of the tail, and on them the iiooks form 

 a close series in a single row. The hooks are distinguished 

 by their elongated basal region, which has a median con- 

 vexity, then curves upward at the anterior edge, which has 

 a small process for the ligament. A process occurs on the 

 anterior margin about its middle, a double curve meeting at 

 this point. The large fang is well developed, and has only 

 a single tooth above it in a lateral view. The posterior 

 margin has a deep incurvation. The hooks vary chiefly in 

 the shape of the basal region. 



The next and eighth form, Lanice conchilega, Pallas, is 

 everywhere distributed on tiie sandy shores of Britain. 



The cephalic region is distinguished by its comparatively 

 small dorsal collar, the rim, however, expanding at each 

 side into a great lateral flap which in some almost meets its 

 fellow of the opposite side in the mid-ventral line behind 

 the lower lip, its outline in this region forming a V. In 

 others, the union of the lateral regions is more complete 

 ventrally, some fusing so as to form a continuous band with 

 only a slight concavity in front, thus probably indicating 

 the normal condition as a complete ventral web, the median 

 gap being due to accidents. A marked characteristic is the 

 disposition of the anterior margin of the tentacular surface, 

 for it is contracted into a frilled spout-like border sur- 

 rounding the mouth — except in violent protrusion. \\'itliin 

 the aperture are two folds, an outer smaller and an inner 

 larger tongue-like fold. Cunningham and Kamage consider 

 the large lower lip and the absence of eyes characteristic of 

 Lanice as contrasted with Terebella. 



The tentacles have the usual grooved structure, and form 

 a dense mass of mobile organs. In the centre of the living 

 tentacle under pressure a pale band of muscular fibres pro- 

 ceeds from the base to the tip. The other parts of the wall 

 appear to consist of an inextricable series of muscular fibres 

 — longitudinal, transverse or circular, and oblique. In the 

 interior of the tentacles are numerous cells, but whether 

 free or adherent is not evi lent, though they do not separate 



