157 



ova-bearino- female from Stat. 74 32,5 and 19 mm., so that the carapace appears in the adult 

 one and two-thirds as long as high. 



As results from the Table of Measurements the rostrum of full-grown specimens is usually 

 a little longer than the carapace, more rarely both are of equal length; in younger individuals 

 it is comparatively much longer, so that in the youngest specimens from the .Stations 5 and 1 2 

 the rostrum appears twice as long as the carapace. The slender, tapering rostrum runs at first 

 downward for about half its length, while the distal part is more or less upturned, so that the 

 apex is sometimes situated at the same level as the postrostral crest, in other specimens far 

 above it. The upper margin is usually armed with 10 teeth, more rarely with 9 or 1 1 and 

 constantly the two first stand on the carapace behind the orbital margin ; these teeth are 

 rather small, not prominent, placed at nearly equal distances from one another and reach to 

 near the tip. The lower margin bears usually 8 teeth, more rarely 7 or 9 and in two ova- 

 bearing females only 6 teeth were observed; these teeth are much larger than those of the 

 upper margin, though they gradually diminish in size. A rare exception is shown by an ova- 

 bearing female (\" 26 of the Table): besides the two teeth on the carapace there are only 3 

 on the upper margin, of which the anterior stands midway between the distal extremity of the 

 antennular peduncle and that of the antennal scale, so that more than half the length of the 

 upper margin is smooth and unarmed. The rostrum is continued nearly to the posterior margin 

 as a prominent, though obtuse carina: in very young specimens it is less distinctly developed 

 on the cardiac region and the gastric portion, that carries the two first teeth, appears therefore 

 comparatively higher than in older individuals. 



As already observed, there is no trace of the postocular carina, but the postantennular 

 and the postantennal carina run uninterruptedly from the posterior border of the carapace to the 

 orbital and branchiostegal spines. The two carinae, though nearly parallel, are on the branchial 

 region a little farther distant than anteriorly. The slender, acuminate, orbital spine extends, 

 beyond the 2°^^ joint of the antennal peduncle, to the middle of the corneae of the eyes; the 

 branchiostegal spine is much shorter and reaches only to the middle of the 2"^ joint of the 

 antennal peduncle. Inferior marginal carina well-developed. In full-grown specimens the cardiac 

 region is more or less rugose between the postrostral crest and the post-antennular carina and 

 in the adult female from Stat. 74 one observes a short elevated line just below and parallel 

 with the post-antennular carina, somewhat farther distant from the post-antennal carina than 

 from the other. 



Abdomen nearly one-third longer than carapace and rostrum combined. The i'' and 2"'' 

 terga are not only not carinate, but appear even slightly concave dorsally, especially the second. 

 Like in other species the i^' tergum bears four tubercles in a transverse line parallel with the 

 posterior margin ; these tubercles show each an impressed point and the two lateral are a little 

 farther distant from one another than those of the submedian pair. The 3^^ tergum is armed 

 with an acute, compressed spine, that arises in the adult species from a little more than 

 the anterior half of the somite, strengthened on each side at its base by a faint oblique 

 ridge that runs from the anterior border to the upper curved margin of the spine; the two 

 ridges are in young specimens almost invisible. In the adult species the posterior margin of 



