6i 



out, the tergal and carinal margin confluent and convex, and the basal margins also confluent 

 and strongly convex. 



The rostrum is the largest of the valves in the lower whorl. It projects freely for 

 about half its length and has the umbo at the apex which is pointed. Its shape is triangular 

 with the sides hollowed out. 



The rostral and carinal latus are of about the same size and shape: triangular, 

 with the apex projecting from the surface of the capitulum. 



The infra- median latus has about the same shape but is much smaller. 



The sub-carina much resembles the rostrum; it is slightly smaller however and stands 

 out in a more horizontal direction. 



The peduncle is short, wide at the summit, slightly narrower only at the base. The 

 calcified scales are very small and not arranged very regularly. They are placed rather close 

 to one another and extend from the surface as bluntly-conical papillae. 



Size. The length of the capitulum of the largest specimen was 4 mm., the total length 

 6,3 mm. The other specimens are but slightly smaller. 



The study of the structure of the hermaphrodite animal contained within the capitulum 

 has yielded the following results. 



Mouth placed near the adductor muscle; elongated in a vertical direction. Labrum 

 not very swollen, slightly elongated in a longitudinal direction; crest without distinct teeth; 

 palpi minute, triangular in outline, with the apex blunt. Apex and outer margin with rather 

 numerous hairs. 



Mandibles with four teeth and the lower angle delicately pectinated. Two very minute 

 teeth are inserted in the cavity between the first and the second tooth ; upper side of the fourth 

 tooth pectinated. Surface of the mandible near the toothed edge covered with very delicate hairs 

 placed in groups of two or three ; inferior margin clothed with longer hairs. 



Maxillae short and broad; two stronger spines and one or two smaller ones at the 

 upper end of the edge; a small notch beneath the upper pair and a single spine planted at 

 its base. The inferior part of the edge forms a sharp angle with the under margin and bears 

 7 to 8 pairs of spines. On the outer surface numerous groups of hairs (three or four in a group), 

 near the spine-bearing edge. 



Outer maxillae rather stout, of oval shape with long bristles on the outer surface. 



Cirri. First pair not at a considerable distance from the second. Rami slender and 

 not very unequal in length. The longest has 8, the .shortest 7 segments. Upper segments 

 slightly narrower than the basal ones; the latter slightly protuberant at the extremity. Spines 

 relatively long, some of those on the outer segments more than twice as long as the segment. 



Second cirrus with rather short rami of 9 segments, lower segments short and broad, 

 upper segments more elongate; 3 pairs of longer spines on the anterior margin as a rule. 



The four posterior pairs with their segments, especially the terminal, much elongated. 

 The middle segments more protuberant anteriorly than the others. The segments bear as a rule 

 three pairs of longer spines and a fourth (sometimes even a fifth) pair much more delicate on 

 the front aspect. Dorsal tufts of three or four spines at the extremity of each segment. 



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