PRIONOSPIO MALMGRBNI. 215 



Habitat.-— Procured in the tow-net attached to the trawl off Balbriggan, Ireland ; 

 Ardfry, Galway Bay; Irish Sea; Blacksod Bay and Clew Bay (Southern). 



The minuteness of the preserved specimens made it difficult to determine the 

 presence or absence of a cephalic ridge, but so far as could be seen it was present. The 

 head terminates anteriorly in a truncated snout, with four eyes, two rounded, anterior 

 composed of several crystalline spheres and dark pigment, and after an interval two 

 elongated or kidney-shaped masses of pigment. This form is thus in contrast with 

 the Canadian, in almost every example of which, as mentioned, the extended pro- 

 boscis had distorted the snout. The proboscis in the latter had a slightly tapered 

 basal process with a button-like tip. A much more prominent cephalic ridge occupied 

 the centre of the dorsum, and terminated posteriorly in a pointed process like an adnate 

 tentacle. It closely agrees, however, with P. Malmgreni of Claparede. 



The body is elongated, resembling posteriorly that of a small Nereid, but anteriorly 

 characteristically enlarged, and gently tapering posteriorly to the vent, which has two 

 cirri. Claparede's examples were all small, viz., 11 — 12 mm., yet the females were 

 mature, a bunch of orange ova occurring on each side of the intestine behind the 

 fifteenth segment. 



In his original description Malmgren states that there are four pairs of branchiae, 

 the basal region of the long tapering forms as pinnate, the distal as filiform (referring 

 to the elongate pinnate cirri of the front and rear of the anterior region). He, however, 

 observes that these are longer than the branchiae of his second and third segments (for 

 he apparently overlooked the minute anterior feet) ; yet he does not differentiate these 

 from the dorsal lamella of the feet, which are truly " ovate-lanceolate," whilst the true 

 branchiae, which he apparently represents in his Eig. 55a, Taf. X, are broadly strap- 

 shaped, only a little tapered at the tip, which ends in a conical process or mucro. 

 Moreover, they are closely striated transversely and richly ciliated, whereas the pinnate 

 processes and the lamella of the feet are not. Claparede, again, expressed doubt as to 

 the actual number of branchiae from the facility with which these delicate organs break 

 off. He, however, considered the pinnate cirri as branchiae, though he found no cilia on 

 them. In his figure (Plate 22, fig. 3) none of the ligulate (true) branchiae are shown, 

 and the position of the posterior pair of the pinnate cirri is faulty. 



In the first foot the dorsal and ventral lamellae are rounded and rudimentary, and 

 the tufts of bristles small ; moreover, the granular condition of the axis of the bristle was 

 not made out. The second foot has the dorsal lamella of a lanceolate outline, whilst the 

 ventral is rounded. Both dorsal and ventral bristles showed a granular condition of the axis, 

 so that it (axis) appeared to have minute transverse bars in the centre (Plate I, fig. 6). 



In the third, fourth, and fifth feet the dorsal lamella largely increases in size as a 

 broadly lanceolate process, but in the third and fourth it is considerably less than the 

 elongate branchia which forms a conspicuous process on the inner side of each, and readily 

 distinguished by the transverse lines. These branchiae are much longer than those in the 

 Canadian form, and the tip differs in its tapered condition. They are also proportionally 

 larger and longer than in the P. plumosa of Sars. The first ten segments are con- 

 spicuously bristled, the strongly curved dorsal and ventral bristles projecting laterally in 

 front of the lamellae. The eleventh has more slender capillary bristles. Claparede stated 



