648 CRUSTACEA. 



CTRTOPIA ROSTRATA. 



Carapax bene acuteque rostratus, rostro oculis non breviore, margine cara- 

 pads ittfero-laterali acute uni-dentigero, postico rotundato. Segmenturn 

 abdominis ultimum extremitate subito angustatum apiceque rotun- 

 datum et minute spinulosum, ad basin setarum subapicalium spind 

 armatum ; setis (vel barbis) longis apicem valde superantibus, divari- 

 catis. Lamellae caudales subcequce, segmento caudali valde breviores. 



Carapax with an acute beak rather long (as long as the eyes), bearing 

 an acute tooth somewhat posteriorly on the luteral margin, rounded 

 behind. Last abdominal segment abruptly narrowed at extremity, 

 and the small apex rounded and set divergently with spinules ; a 

 spine also at outer base of subapical setae; these subapical setae 

 extending much beyond the apex of the caudal segment and diver- 

 gent. Caudal lamellae subequal, very much shorter than the caudal 

 segment. 



Plate 43, fig. 2 a, animal, enlarged ; b, caudal extremity. 



Pacific, Kingsmills Group, near Pitt's Island. Collected, April 30, 

 1841. 



Length, one-third of an inch. Colourless. The beak is quite long 

 and acute. The carapax is not excavate behind across the dorsum. 

 The caudal lamellae are about three-fourths as long as caudal segment, 

 and the setae projecting and divergent give it a sagittate appearance. 

 These setae or setiform processes extend full half their length beyond 

 the apex of the segment ; and there is a spine on each side of the seg- 

 ment just exterior to base of setse. The eyes are gibbous and look as 

 if a mass had been protruded laterally by pressure. The legs were 

 imperfect ; only one pair was elongated, as seen in the figure. 



The base of the inner antennas is about three times as long as the 

 eyes. First joint nearly two-thirds the length of the whole; third 

 joint a little longer than the second. Apex of first joint prolonged as 

 far as apex of next segment ; only a few short hairs on these basal 

 joints. At apex of base two one-jointed branches, as long each as 

 third joint of base ; and also one or two long plumose processes on 

 under side, which are three times as long as the branch. 



