PSEUDOCLYMENE QUADRILOBATA. 337 



shallow notch and a fold occur on each side, whilst the rim posteriorly dips to a median 

 notch. Narrow keel arises somewhat behind a line between the lateral notches and rims 

 forward to the mid-frontal process. It has a groove on each side, but the curved nuchal 

 grooves proper are anterior in position and short. On the ventral aspect of the mid- 

 frontal process a dark band exists, and this may indicate the presence of eyes in life. 

 Mouth a transverse slit with prominent, furrowed lips. Proboscis apparently smooth. 

 First seven segments markedly glandular, first three bear spines with slightly curved shafts 

 and tips, that of the third segment having the tip most curved. Stronger bristles with 

 straight shafts, tapered tips and distinct wings, the wing ending distally in a peculiar 

 flattened region which is continuous with the slender tip, but no distinctly spinous 

 condition observed; the delicate, slender forms tapered to fine hair-like tips. Hooks 

 commence with modified forms on the fourth bristled segment. The typical hook is 

 distinguished by the great breadth of the distal end, the large angle made by the main 

 fang with the neck, the close application of the gular bristles to the lower border of the 

 fang, and the numerous small teeth on the crown behind it ; yet the crown is rounded off 

 instead of being high. The shaft is of moderate length, striated longitudinally, gently 

 curved, the slope from the slight shoulder to the neck is gradual, and the obliquely striated 

 neck dilates in its progress distally. Tube free, composed of sand and shell-fragments. 

 Arwidsson found one fixed to Lima excavata in Norway. 



Synonyms. 

 1856. Clymene quadrilobata, Sars. Fauna Lit. Norveg., ii, p. 15, Tab. 2, figs. 18 — 22. 

 1865. „ „ De Quatrefages. Annel., t. ii, p. 241. 



1900. Euclymene (Praxillella) quadrilobata, Verrill. Trans. Conn. Acad. Arts Sci., vol. x, p. 655. 

 1906. Pseudoclymene quadrilobata, Arwidsson. Skand. u. arktisch. Maldan., p. 236, Taf. vi, figs. 



181—186, Taf. x, figs. 321—329. 

 1913. „ „ Mcintosh. Ann. Nat. Hist., ser. 8, vol. xi, pp. Ill, 128. 



Habitat. — Dredged in 70 fathoms in the Outer Haaf, Skerries, Shetland, 1868, by 

 Dr. Grwyn Jeffreys, of whose successful labours, along with those of Canon A. M. 

 Norman, mention has so often been made. Abroad it has been procured in various 

 localities off the coast of Norway (Sars, Arwidsson). 



In this form the cephalic plate is distinguished by the prominence of the lateral 

 margin on each side of the small mid-frontal process — approaching Amvidssonia zetlandica 

 in this respect, though the lobes are less and the frontal process is larger. The margin, 

 indeed, is conspicuous all round, and in place of the deep notch of Praxillella a shallow 

 notch and a fold occur laterally, whilst posteriorly the margin dips downward gently to a 

 median notch, which is thus less abrupt than in Praxillella prxtermissa. The outline of 

 the cephalic plate is ovoid, and the keel arises rather behind a line between the lateral 

 notches, and passes forward as a narrow ridge to the mid-frontal process. A groove exists 

 on each side of it, but the nuchal grooves proper seem to be short and anterior in position, 

 forming two curved furrows with the convexity outward, which, anteriorly, debouch on 

 each side of the mid-frontal process. On the ventral aspect behind the frontal process 

 is a dark band, but no distinct eyes are now observable. The mouth forms a transverse 

 slit, with prominent furrowed lips anteriorly and posteriorly and radiating grooves 

 laterally. Arwidsson describes the proboscis as provided with papillaa. 



166 



