424 DE. J. G. DE MAN ON CEUSTACEA CHIEFLY 



The two egg-bearing females are respectively 33 mm. and 32 mm. long from the tip 

 of the rostrum to the end of the telson, the carapace of the former being 12 mm. long, 

 of the other 11"5 mm. ; the young specimen is 22'5 mm. long, the carapace 8 mm. The 

 carapace, rostrum included, measures little more than one-third of the whole length. 

 The rostrum of the two larger specimens reaches to the distal end of the second joint of 

 the antennular peduncle, that of the youngest individual little beyond the middle of that 

 joint. In the largest specimen the toothing-formula of the rostrum, which closely 



resembles fig. 1 of plate 110 of the ' Challenger ' Report, is -^; the first tooth, twice as 

 far distant from the second as the second from the third, is little larger than the second, 

 but the diS'erence is not so great as on that figure. The distance of the first tooth from 

 the frontal border is a little more than one-third the length of the carapace (rostrum 

 excluded) ; two teeth are on the cephalothorax, the third is placed above the frontal 

 margin. The foremost tooth is as far distant from the penultimate as from the pointed 

 tip, which is situated on a somewhat lower level than the upper border of the carapace. 

 The four teeth of the lower margin occur on its distal half and are considerably smaller 

 than the upper ones ; the first is situated just below the middle of the penultimate tooth 

 of the upper border, the foremost tooth midway between the tip and the foremost one 



Q 



of the upper margin. In the other ova-bearing specimen the toothing-formula is -5 , 

 just as in the ' Challenger ' specimen of Nauticaris tmirecedens, and three teeth are on 

 the carapace, the fourth immediately before the frontal border ; the foremost tooth is 

 once and a half as far distant from the tip as from the penultimate tooth. Of the four 

 small teeth of the lower margin, the first is situated just below the base of the foremost 

 tooth of the upper margin, the two anterior in front of it. Except the first, the teeth 

 of the upper border are equidistant, like those of the lower margin. 



The rostrum of the youngest specimen shows the formula ^; two teeth are on the 

 carapace, the third above the frontal border ; the foremost tooth of the upper margin, 

 is a little farther from the tip than from the penultimate; of the four very small 

 teeth of the lower margin, the first and the second are situated below the foremost 

 tooth of the upper margin, the third and the fourth in front of it. In this youngest 

 individual the tip of the rostrum is situated at the same level as the upper surface 

 of the carapace. The slender antennal tooth reaches the cornea of the eye- 

 peduncles; the pterygostomian spinule is small and sharp, though distinct in the 

 three specimens. 



The abdomen is rounded and smooth. The postero-lateral angle of the fifth segment 

 terminates in a sharp point, much sharper than it appears in the quoted figure 1 of the 

 'Challenger' Report. The sixth segment is once and a half as long as the fifth; in 

 Spence Bate's figure it appears shorter than the fifth, but, as is shown above, this figure 

 is inaccurate. The postero-lat;eral angle of the sixth segment is acute, but not movable. 

 The telson, which is not quite twice as long as the sixth segment, tapers posteriorly to 

 the obtuse posterior border, which is in the middle acute and M'hich, fringed, like the 

 lateral margins, with ciliated setse, carries on either side two movable spinules, of which 

 the inner are much longer than the outer. The somewhat flattened upper surface carries 



