171 



almost quite free and uncovered. Pterygostomian angle rounded. Pleura of the sixth abdominal 

 somite articulate, movable. 



Antennal region as in Arete, but the stylocerite shorter. Only one cheliped is known, 

 and this leg agrees with the small cheliped of Arete. Merus short, not vaginiform : carpus short, 

 cyathiform; chela turned outward, compressed, with both margins entire, but with a small groove 

 on the upper (inner) face of the palm, just behind the articulation of the dactylus. Fingers 

 shutting close together, with rather sharp, cutting-edges, that of the dactylus finely denticulate. 



Legs of the second pair with the carpus 5 -articulate, the five segments as in the genus 

 Syiialp/ieus, the second to the fourth being very short, equal, the first the longest, the fifth a 

 little shorter than the first. 



Ischium of the following legs with a movable spine near the base. Merus unarmed at 

 the apex of the lower margin. Dactylus biunguiculate. 



f I. Aretopsis amabilis de Man. 



J. G. DE Man, in: Tijdschr. d. Ned. Dierk. Vereen. (2) Dl. XI, 1910, p. 311. 

 Stat. 8g. June 21. Pulu Kaniungan ketjil. Reef, i specimen. 



Looked at from above, the rostrum that extends to just beyond the first antennular 

 article, appears acute, triangular, rather wider at its base than long, with slightly concave, 

 divergent, lateral margins; the upper margin that projects horizontally forward, is obtusely 

 carinate. In a lateral view, however, the rostrum appears strongly compressed laterally, 

 like in the genus Athanopsis^ half as high as long with rounded tip and with the 

 arcuate lower margin curving backward and downward. There is no trace of supra-corneal or 

 extra-corneal teeth, but, like in the genus Arete, the outer angle of the orbits is acute, denti- 

 form and reaches to midway the eye; above this triangular tooth the orbital margin, i.e. 

 the continuation of the lateral margin of the rostrum, appears concave without any prominence. 

 Beneath the outer angle of the orbits the antero-lateral margin of the carapace is directed 

 vertically downward and the pterygostomian angle is rounded. The upper border of the some- 

 what compressed carapace is straight. 



The pleura of the sixth abdominal somite are articulate, movable. Telson moderately 

 tapering, its length equals 3,5-times the width of the posterior margin, the latter half as wide 

 as the greatest width near the base ; posterior margin truncate in the middle, this truncated 

 part just half as broad as the width of the margin. There are two spinules near the outer 

 angles that are not prominent at all; the inner, longer spinules measure a little more than 

 one-third the width of the posterior margin, beyond which they extend by half their length ; 

 the outer spinules measure one-fourth of the longer. The spinules of the upper surface are 

 situated not far from the lateral margins and are rather short, measuring one-fourth the width 

 of the posterior margin ; anterior pair just before the middle, the proportion between the length 

 of the telson and the distance between this pair and the posterior margin being i,S; posterior 

 pair a litde farther distant from the posterior margin than from the anterior pair. Anal tubercles 

 probably wanting. Distal margin of the uropods truncate. 



39 



