94 THE VOYAGE OF H.M.S. CHALLENGER. 



or twenty -four-jointed, longer than the cephalothorax, the basal joints very indistinctly 

 separated, rather sparingly setiferous ; right antenna of the male (fig. 3) having two 

 denticulated joints, the proximal end of the first' plate forming a free sub-crescentic or 

 club-shaped process, which bears a series of broad recurved teeth, following which is a 

 row of six or seven still larger spines, graduated in size from the middle, where they 

 are longest; the teeth of the main portion of the plate, as also those -of the following 

 joint, are very fine and close-set ; the antepenultimate joint is produced externally into a 

 dagger-shaped, adpressed spine, equal in length to the penultimate joint. The joints of 

 the right fifth foot in the male (fig. 11) are all broad and subquadrate, the third bearing 

 a long curved terminal claw, and a similar immovable finger at its upper angle ; the third 

 joint of the left side has two apical spine-like setae, and two small roughened or tuber- 

 culated finger-like papillae (figs. 12 and 13). The fifth foot in the female (fig. 10) 

 has a broad quadrate basal joint, to which are attached two simple, curved, one-jointed 

 branches, the inner only half as long as the outer. The abdomen of the male (figs. 18, 19) 

 is five-jointed, and sometimes has the ventral angle prominently spined; the female 

 abdomen is two-jointed (figs. 14-17), and usually has the lower margins of the segments 

 irregularly fimbriated or spinous ; the first segment has also on the ventral aspect three 

 or four slender curved processes of variable size. The second tail seta, counting from 

 the inside, is usually longer than the rest. 



Habitat. — Arafura Sea, lat. 8° $., long. 136° E.; off Sibago Island and at other places 

 amongst the Philippine Islands. 



This species — unless two or three are here mixed up under one specific name — is 

 subject to a good deal of variation, especially in the peculiar distortions or outgrowths of 

 the abdominal somites, some of which are figured in our plate ; the fifth pair of feet, also, 

 in both sexes, presents minor variations of form. 



Several species very nearly allied to this have been described by different authors, 

 but none of them seem to admit of complete identification with it. Among its very near 

 relatives may be mentioned Pontella strenua and Pontella valida, Dana ; Pontella 

 helgolandica and Pontella gigantea, Claus, and Labidocera darwinii, Lubbock. 



*** Head with lateral spines ; apex of posterior foot-jaw six-jointed. 



7. Pontella elef has, n. sp. (PL XXXVIII. figs. 7-14). 



Length, l-8th of an inch (3 mm.). Cephalothorax pointed in front, with recurved 

 spines on each side of the head, posterior angles rounded off. Anterior antennae shorter 

 than the cephalothorax, twenty- three-jointed (fig. 8), densely setiferous towards the base, 

 more sparingly beyond. Eight anterior antenna of the male (fig. 9) thick and short ; the 

 teeth of the one denticulated plate (figs. 10, 11) are short and stout, and blunt at the 



