I JO 



reaches a little beyond the first antennular article, is t w i c e as long as broad at its base and 

 shows therefore a more slender form than the rostrum of Ar. Maruteensis. At either side 

 of the rostrum one observes a slight rounded prominence, the tracé of the supra-corneal 

 spines, which, according to the figure, are in Ar. Maruteensis acute. 



Second antennular article one and a halfas wide as long, s hor ter than the visible 

 part of basal article and only half as long as the third ; stylocerite curved, acute, reaching 

 to the transverse suture of the third article. The undivided part of the outer flagellum consists 

 of 5 articles that are broader than long. Carpocerite a little longer than the antennular peduncle, 

 stout, one and a half as long as thick ; scaphocerite as long as the antennular peduncle. 



The length of the telson equals 3,5-times the width of the posterior margin, proportion 

 between the width at the base and that of the posterior margin 1,9. Spinules of the upper 

 surface small, measuring 1 / 1B the length of the telson and placed near the lateral margins, the 

 anterior pair a little behind the middle, the proportion between the length of the telson and 

 the distance of the anterior pair from the posterior margin being 2,3; proportion between the 

 distances of both pairs from the posterior margin 1,8. Posterior margin slightly convex, the 

 outer angles obtuse; inner longer spinules measuring one-third the width of the margin. 



The chelipeds are equal and closely resemble the small cheliped of the female of Ar. 

 Maruteensis (H. Coutièke, 1. c. 1905, p. 21, Fig. 4, the left). The cutting-edge of the triangular 

 immobile finger is finely denticulate along its whole length, that of the tapering dactylus is entire. 



Second legs also as in Ar. Maruteensis. Merus 3-times as long as wide. Carpus 1,12- 

 times as long as the merus, 5-times as long as thick at distal extremity; the four segments 

 are 0,42 mm., 0,14 mm., 0,14 mm. and 0,24 mm. long. Chela 0,63 mm. long, one and a half 

 as long as the first segment of the carpus, fingers half as long as the palm. 



The following legs show a somewhat less stout shape than those of Ar. Maru- 

 teensis. Relative dimensions of the third pair: merus 2: carpus i; propodus 2. The merus is 

 3,35-times as long as wide, but for the rest fully resembles that of Ar. Maruteensis, being 

 truncate at the distal extremity, with only a minute tracé of an apical tooth. Carpus twice as 

 long as thick at the distal end. Propodus not 4-, but 5-times as long as wide, with 7 short 

 spinules on the posterior margin and two longer ones at the far end. 



Dactylus one-third of the propodus, of a rather stout shape, 2,6-times as long as broad 

 at its base; ventral accessory hook much shorter and smaller than the principal one. The ischium 

 appears also a little less stout than in the typical species, being one-third longer than wide distally. 



The typical species has been observed at the island of Marutea (Paumotu-islands). 



Aretopsis de Man. 

 J. G. DE MAN, in: Tijdschr. d. Ned. Dierk. Vereen. (2) Dl. XI, 19 10, p. 310. 



A new genus of the Alpheidae, closely related to Arete Stimps. 



Looked at from above, the rostrum appears acute, triangular, carinate, without any 

 tracé of supra-corneal teeth ; in a lateral view it appears strongly compressed with the tip 

 rounded, like in the genus Athanopsis Cout. Extra-corneal teeth wanting, infra-corneal teeth 

 (outer angles of the orbits) acute, dentiform. Eyes as in the genus Arete, cornea antero-lateral, 



38 



