69 



directed obliquely outwards. The eyes moderately small, semi-globular, black; the eye-stalks on 

 the whole conical, at the end slightly broader than the eyes; their distal joint considerably 

 broader than long. The antennulje with the third joint of the peduncle a little more than twice 

 as long as broad, terminating above and below in the processes mentioned in the description 

 of the genus; the inner flagellum slightly longer than third peduncular joint, very slender, 

 with 6 joints. 



Sixth abdominal segment a little longer than the sum of the two preceding segments 

 (fig. 5«). The female pleopods simple, styliform (fig. 5 «), the anterior pairs very short, last pair 

 longer but yet short. The uropods (fig. 5 i) slender ; the e.xopod at least eight times as long 

 as broad, rather little longer than the endopod and more than two and a half times as long 

 as the telson; the setee on the distal end and along a part of the inner margin of both rami 

 extremely long. Telson (figs. 5 i and 5 k) short, slightly longer than broad, narrowing strongly 

 backwards, with the proximal half of the lateral margins very convex ; the posterior end is 

 nearly three and a half times shorter than the breadth of the telson somewhat behind its base, 

 with the lateral corners produced into very oblong-triangular, acute processes separated by a 

 proportionately deep and broadly rounded incision, at the middle of which originate a pair of 

 feathery setee almost as long as the telson. — Colour light reddish, without spots. 



Length of one of the females with the marsupium rudimentary 4.8 mm. 



Remarks. — On fig. 5^ the small, still feebly developed marsupial plate of the last 

 thoracic leg is seen directed backwards, which seems to be its natural position. 



Arachnomysis Chun. 



Description. — Carapace anteriorly abbreviated (PI. XI, fig. id), without frontal plate 

 and terminating somewhat behind the origin of the eye-stalks ; the front margin is transverse with 

 acute teeth or processes, and the antero-lateral corners are produced into an acute, triangular 

 lobe directed outwards; each lateral margin of the carapace somewhat behind the middle with 

 an oblong-triangular, spiniform process, and the part of the carapace between the front end and 

 that pair of lateral processes is narrow, covering only the upper surface and the upper part of 

 the sides of the cephalothorax, while behind the processes the carapace is gradually widening 

 and posteriorly emarginate, leaving the posterior part of the cephalothorax uncovered. The 

 eye-stalks with their eyes even a little longer than the peduncle of the antennuls, pellucid, 

 so that the nervous elements are visible (fig. i c) ; the proximal joint of the stalks is long and 

 slender (fig. i 6), the distal joint conical, increasing gradually somewhat or much in thickness to 

 the retina, which is feebly convex ; the structure of the eyes reminds of that in larval Sergestidse. 

 Antennulae normal; first and third peduncular joint nearly equal in length; male lobe thick and 

 somewhat protruding. Antennae without squama, but the joint otherwise bearing this plate is 

 on the outer side produced into a triangular, acute process directed outwards (fig. i d). Labrum 

 rounded in front (fig. id). Left mandible (figs, le and if) with the incisive part and the movable 

 lobe very well developed, while setae are wanting between that lobe and the low molar process. 

 Mandibular palps long and somewhat slender; first joint even longer than broad; second joint 



