374 

 1. Acanthonotosoma serratum, (Fabr.). 



(PI. 131, fig. 1). 



OniscHS serratus Fabricius, Fauna Gr0nlandife p. 262. 

 Syn.: Amphithoe serra, Kroyer. 

 Acanthonotus serra, M.-Edw. 

 ,, Verturnnus serratus, Goes. 



Body rather stout, with the back greatly curved, and distinctly cari- 

 nated throughout the whole mesosome and metasome, the cariua being, how- 

 ever, rather low in the 4 anterior segments, whereas in the remaining ones it is 

 elevated into well-marked, though not very large, posteriorly curving projections, 

 the last of which is somewhat laminar and obtuse at the tip. Urosome 

 without any dorsal projection. Cephalon comparatively short, but rather 

 deep, rostrum evenly curved and acuminate, reaching about to the end of the 

 basal joint of the superior antennae, lateral corners very small, and narrowly 

 rounded at the tip, anterior edges between the latter and the rostrum evenly 

 convex. Fourth pair of coxal plates with the outer part triangularly pointed, 

 and having the anterior edge subangular below the middle, posterior projec- 

 tion of moderate size, and acute at the tip; the 2 succeeding pairs with the 

 posterior lobe strongly deflexed and rather deep, but not acutely produced. 

 Last pair of epimeral plates of metasome divided at the lateral corners into 

 2 slightly diverging, narrow lobes, the lower of which is coarsely serrated on 

 the upper edge, and at the tip; the 2 preceding pairs terminating each in a 

 simple dentiform corner, and being slightly serrated on their posterior edge. 

 Eyes rather small, rounded oval in form, and somewhat narrowed in their upper 

 part, pigment bright red. Superior antennas about equalling X A of the length 

 of the body, 1st joint of the peduncle considerably shorter than the other 2 

 combined, and not produced at the end to any dentiform projection, flagellum 

 scarcely longer than the peduncle, and composed of about 15 articulations, 

 each having anteriorly a dense fascicle of sensory bristles. Inferior antennae 

 considerably shorther than the superior, last joint of the peduncle scarcely 

 attaining the length of the penultimate one, flagellum shorter than those 

 joints combined. Anterior gnathopoda with the basal joint densely setous 

 on both edges, propodos very narrow and shorter than the carpus, dactylus 

 subulate, not dentated, but provided with several curved setae, the outer of 

 which is densely ciliated on the one edge. Posterior gnathopoda somewhat 

 shorter but stouter than the anterior, and also more richly setous, propodos 

 not nearly attaining the length of the carpus, dactylus very short and broad, 

 sublaminar. Pereiopoda moderately strong, basal joint of the 3 posterior 

 pairs rather broad, oval quadrangular in form, and having the infero-posteal 

 corner produced to a triangular lobe. Last pair of uropoda with the inner 



