320 LEIOCHONE CLYPEATA. 



7 d and 7 e) in proportion to the length of the neck, and the shaft is also long and tapering, 

 as well as curved like a bow. The transverse diameter of the crown from the tip of the 

 main fang backward is only a little less than the entire length of the distal region from 

 the shoulder upward, and the crown is more or less flattened. The main fang leaves the 

 neck at a little more than a right angle, and the stiff gular bristles are closely applied to 

 its lower outline, and then curve like a crest over it. There are more than seven teeth 

 above the main fang, and bold strise pass from these and the great fang down the neck 

 and join those in the shaft. Moreover, the second quarter, or sometimes the middle third, 

 of the shaft is marked by slightly oblique striae. 



It was at first thought that this was a large variety of Leiochone ebiensis, but the 

 structure of the cephalic region, that of tlie anal funnel with its cirri, and the structure of 

 the hooks warranted separation in the meantime. The specimens were kindly forwarded 

 by Dr. Assheton, who procured them during a dredging expedition in Scotland. 



The hooks differ from those of Leiochone polaris of Theel, 1 since that form has 

 only three teeth on the crown behind the great fang, and a space occurs between the 

 gular bristles and the base of the fang. Moreover, in L. polaris only a single cirrus 

 occurs on the anal rim. 



4. Leiochone clypeata, Be St. Joseph, 1 894. Plate CIX, figs 11 and 11 a — bristle and hook. 



Specific Characters.— Cephalic plate nearly transversely truncated, only a slight 

 inclination downward and forward being noticeable. Outline somewhat ovoid, and the 

 erect rim is not much developed and has a shallow excavation in place of the lateral notch 

 on each side. A short, bluntly-conical median frontal process is continuous with the narrow 

 keel, which extends nearly to the posterior border. Nuchal grooves appear to commence 

 near the posterior end of the keel and diverge as they pass to the anterior border on each 

 side of the frontal process. Body nearly cylindrical behind the cephalic region, but 

 diminishes toward the caudal funnel. The anterior segments are richly supplied with 

 glandular belts and patches, but the posterior are more translucent, though glands are 

 also present at the rows of hooks. The ventral streak is faint so that posteriorly the 

 dorsal and the ventral surfaces are not readily distinguished. This (posterior) region has 

 a moniliform series of about nine narrow, bristled segments, which are urn- shaped. Two 

 unarmed rings follow with the funnel, which externally is shaped like a dice-box, with six 

 equal, moderately long, subulate cirri and a slightly longer seventh in the mid-ventral line. 

 Anus in the centre of the terminal cup, without an anal cone. 



Bristles in two groups ; stronger pale yellow forms nearly straight and with tapered 

 tips and wings, and slender translucent bristles with very fine hair-like bristles and 

 spinous edges. The first three segments have spines, the shafts of which are slightly 

 curved in the third foot and have bluntly-conical points. Modified hooks without gular 

 bristles occur on the fourth segment. The typical hook is rather short, with curved 

 shaft, somewhat short neck, broad toward the tip, and curved backward, the main fang 

 making less than a right angle with the neck, and having gular bristles immediately 

 beneath. About seven teeth occupy the high crown behind the great fang. 



i ( 



Kongl. svenska Vet.-Akad. Handl./ Bd. xvi, p. 58, pi. iv, fig. 56. 



