254 Part III.— Tenth Annual Report 



' 27 • 10 ' 7 ' 5 • 3 • 3 • 2 ■ 2 • 11 

 1 • 2 , 3'4-5'6'7 , 8- 9' 



The fourth joint is produced so as to form the base of a long and stout 

 sensory filament All the joints except the first are more or less setiferous. 

 Posterior antennae three-jointed, the joints subequal; a small secondary 

 one-jointed branch springs from the end of the first joint. Mandible 

 palp distinctly two-branched — one of the branches much larger than the 

 other (fig. 22), Maxillae with a broad biting part and a four-lobed 

 branchial appendage. Anterior foot-jaw five-jointed ; the broad first and 

 second joints bear five marginal, digitiform, setiferous lobes arranged iii 

 two groups — three lobes in the one and two in the other, with a cle^r 

 space between. The last three joints, which are very small, are furnished 

 with a number of small setae. Posterior foot-jaw three-jointed, last joint 

 forming a base for a moderately long terminal claw and a small seta ; 

 a plumose seta springs from the inner margin, and near the middle of the 

 second joint, anterior to the plumose seta, are a number of fine marginal" 

 cilia. The first joint is furnished with two subterminal plumose hairs. 

 The first four pairs of swimming feet are nearly as in Tetragoniceps 

 maleolata. The fifth pair, which are one-branched, are in the form of 

 large, foliaceous concave plates, the length of which is about one-third the 

 length of the whole animal (fig. 30). Their breadth is about equal to half 

 their length. The extremity and outer margin are provided with a few setae, 

 the inner terminal seta being plumose, the others plain. A strong muscle 

 extends down the exterior side and across the extremity, and sends off 

 branches to the marginal setae. Inclosed within the feet were a 

 number of ova, having apparently no other covering than that of the 

 enclosing large foliaceous plates. Abdomen five-jointed ; the posterior 

 ventral margin of the third segment is produced so as to form a prominent 

 fold which extends about half-way over the next segment. Caudal 

 stylets about as long as the last abdominal segment, and having the outer 

 margin nearly straight and the inner strongly sigmoid ; each stylet bears 

 a long terminal seta, the base of which is considerably dilated, and a few 

 very small hairs, as shown in figure 32. No males were obtained. 



Habitat. — Off St Monans. Kare. The nine-jointed anterior antennae, 

 with the strong claw- like process of the second joint, together with the 

 remarkably large, foliaceous fifth feet, render this a well-marked 

 species. 



Tetragoniceps incertus. \ (PI. XII. figs. 1-17). 



Female. — Body elongate, cylindrical ; length, exclusive of caudal setae, 

 1 mm. First cephalo-thoracic segment about as long as the next two 

 together, forehead produced into a sharp-pointed rostrum. Anterior 

 antennae about as long as the first body segment, seven-jointed, the 

 proportional length of the joints as shown in the formula 



20; 18 • 12 • 7 • 4 -5 • 8 

 1 • 2* 3-4'5'6-7* 

 All the joints except the first sparingly setiferous ; a moderately long 

 olfactory filament springs from the end of the fourth joint. Posterior 

 antennae short, two- (or three- 1 ) jointed, and possessing a very small one- 

 jointed secondary branch which bears two terminal setae. The apex of the 

 last joint of the primary branch is furnished with five setae, the three 

 longest of which are bent near the middle, the outer one of the three 

 having a small forward-directed spine at the bend. Mandible dilated at 

 the base, the apex truncate, and armed with several blunt-pointed teeth ; 

 mandible palp one-branched, long, and slender. Maxillae small, simple, with 



