MAGELONA. 217 



cone. The snout had the ordinary truncate anterior border without a trace of eyes, but 

 on the dorsum a cephalic ridge extended along the median line and terminated posteriorly 

 in a pointed process like an adnate tentacle about the line of the third foot. The body 

 presented the normal outline, and when complete probably had about 100 segments, the 

 number given by Malmgren for the northern example. 



The first foot is minute and consists of a fan -shaped dorsal lamella and a smaller 

 ventral one of ovoid outline, one side forming the adherent base. In front of the dorsal 

 is a group of strong tapering bristles with a basal curvature and a very finely tapered tip, 

 the centre of each being minutely granular, whilst the slender tip is homogeneous. The 

 ventral tuft is composed of bristles almost straight, but having as finely tapered tips. No 

 wings could be defined in the bristles of this foot, and the tufts were nearly equal in size. 



In the second foot the dorsal lamella has become broadly lanceolate, its lower border 

 being bluntly rounded, the upper somewhat pointed. The ventral lobe is elongate-ovoid 

 with the free end pointing downward. The curvature of the dorsal bristles is less marked, 

 the centre of the shaft is less distinctly granular, and there is a barely visible trace of a 

 wing. The ventral bristles, on the other hand, are more evidently curved, are larger and 

 of two kinds, longer curved finely tapered forms with minute granules in the shaft and 

 a finely tapered tip without wings, and shorter bristles with translucent shafts, narrow 

 wings, and finely-tapered tips. 



The third foot of the Canadian form has a considerably larger dorsal lamella, and has 

 the pinnate process in front, but it carries no branchia. The next two feet (fourth and 

 fifth), however, bear well-developed branchiae, that following (sixth) having a conspicuous 

 dorsal lamella and a pinnate process on each side. In the succeeding feet the dorsal 

 lamella gradually diminishes, so that at the fourth from the posterior pinnate process both 

 lamellae are much reduced and the capillary bristles thus. rendered conspicuous. Posteriorly 

 the lobes of the feet diminish greatly, whilst the dorsal bristles become longer and so 

 slender as to be hair-like. Ventrally hooks take the place of the anterior bristles from 

 the fifteenth foot backward. In this form the pinnate or papillose cirri were sparsely 

 covered by the somewhat clavate, long papillae, which became shorter and ceased about the 

 commencement of the distal third of the process, and thus contrasted with the condition 

 in the Prionos'pio plumosa of Sars. The dorsal bristles consisted of winged forms and of 

 others in which the wing was not distinct, but which had the axis granular and so 

 arranged in some as to give a transversely barred appearance. In the middle of the body 

 the ventral row of hooks, besides a few very slender capillary forms, had at the ventral 

 edge a single, strong curved bristle. The hooks were rather slender and long, with a 

 main fang and two or three teeth above it in lateral view. The branchia is apparently 

 broader than Malmgren's figure would indicate, and broader than the form described by 

 Sars or in that from the ' Valorous,' but it is less elongate than that of the British form — 

 the Prionospio Malmgreni of Claparede. 



Genus CIV. — Magelona, Fritz Mutter, 1858. 



Moea, Johnston. 



Prostomium elliptical, greatly extended and muscular ; tentacles vascular with large 



151 



