300 DE. J. G. DE MAN ON SPECIES OF PAL^MON 



xlfrican specimens still provisionally under the name given to them by Herklots, because 

 neitlier Aurivillius nor myself was enabled to study also American individuals of 

 FalcRinon acanthurus. It may be possible, indeed, that slight ditfereaces exist between 

 the two species, differences that have been overlooked in the published descriptions, 

 and we must consider that von Martens, who examined American specimens of 

 P. acanthurus together with one from Sierra Leone, was unable to decide whether 

 the latter specimen was to be referred or not to P. acanthurus {vide Archiv f. Naturg. 

 XXXV. Jahrg. 1869, p. 30). 



The rostrum of the male specimen * from Liberia, the cephalothora,x of which is 

 closely covered with minute spinules, differs rather much from all the other specimens in 

 the large collection lying before me. In the first place, it is but little longer than 

 the peduncles of the internal anteniics, much shorter than the scaphocerites, and it 

 extends straight forioard, being not at all upturned at the extremity (PL 18. fig. 13). The 

 11 teeth of the upper margin extend to the tip, there being no smooth interspace 

 separating one or two apical teeth from the preceding. The first two stand on the 

 carapace and are somewhat more distant from one another than the others. One 

 observes 5 teeth along the distal half of the lower margin, the first of which is situated 

 just below the seventh tooth of the upper border. 



The riglit leg of the second pair is almost once and a half as long as the animal, 

 the left is but 4 mm. shorter. As regards the length and tlie shape of the joints, 

 these legs fully agree with tbat of the adult male from the River Prali described below, 

 and the same conformity is observed as regards the number, the form, and the arrange- 

 ment of the spinules with which the joints are beset. Each finger is armed with a small 

 conical tooth, but between this tooth and the articulation there are only two or three 

 smaller teeth ; both fingers of each leg are thickly covered with a woolly felt. The 

 three posterior legs are comparatively just as long as in the adult male from tbe River 

 Prah and agree also in the other characters ; the meropodites of the legs of the third 

 pair are 11'5 mm. long and, in the middle, 1'66 mm. broad. 



The rostrum of the adult male (Table, No. 2) from the River Prah is broken off", 

 only tbe three posterior teeth of the uj)per margin are still present ; two of them are 

 on the carapace, the third just above the orbital margin. The cephalothorax is somewhat 

 roughened anteriorly, especially on the sides, by microscopical spinules, only visible by 

 means of a magnifying-glass. They exist also on the telson. In my first description of 

 P. macrobrachion (I. c. 1879) the carapace is said to be smooth. The anterior pair 

 of spinules on the upper surface of the telson is situated exactly in the middle, the 

 posterior pair just half-way between the anterior and the extremity. The latter 

 ends in an acute median tooth in the middle, on either side of which are inserted the 

 two usual spines; the internal spines extend considerably beyond the median tooth. 



The inner or shorter of the two outer flagelia of the upper antennse are 20 mm. long 

 from their extremity to the end of the peduncle, being slightly longer than the latter ; 



* For the measurements of the body and of the second legs, as also for the toothing of the rostrum, I refer to the 

 Table on p. 321, where the dimensions of 38 specimens are given. The joints of the second legs have been measured 

 along their outer margin. 



