216 STALK-EYED CRUSTACEA. 
In small individuals of this species the rounded lateral expansions of the 
carapace behind the antennal spines are more prominent and the antennal 
spines relatively smaller than in full grown specimens. 
G. willemoesti was discovered by the naturalists of the “ Challenger” Expe- 
dition in 1874. Two specimens were procured south of Amboina, lat, 4° 21’ 
S., long. 129° 7’ E.; depth, 1425 fathoms. 
Gnathophausia brevispinis Woop-Mason. 
Plate J. 
Gnathophausia gracilis, var. brevispinis Woov-Mason, Ann. Mag. Nat. Hist., 6th Ser., VII. 188, 1891. 
Gnathophausia brevispinis Woop-Mason, Ann. Mag. Nat. Hist., 6th Ser., VIII. 269, 1891. 
Gnathophausia dentata Fax., Bull. Mus. Comp. Zool., XXIV. 217, 1893. 
Rostrum somewhat shorter than the remaining part of the carapace, 
slender, gently up-curved, its three margins armed with teeth, those of the 
superior margin the largest. At the base of the rostrum, over the anterior 
part of the gastric region, rises a prominent thin triangular crest, produced 
at the apex to a spine; there are in most specimens a minute denticle near 
the anterior, and one to three near the posterior, end of the crest. Supra- 
orbital spines small, not distinctly defined from the base of the rostrum. 
Antennal spines of moderate length, slender and acute. Branchiostegal 
spines very long, their bases expanded into wing-like processes on each side 
of the carapace. Cervical groove distinct. Dorsal keel obsolete on the 
posterior gastric region, distinct behind the cervical groove and armed with 
a row of small teeth. Posterior dorsal spine rather short, scarcely projecting 
beyond the first abdominal somite ; it is directed upward at a much stronger 
angle than is common in this genus. Near the infero-posterior angles of the 
carapace are two spines, the upper of which is long and slender, equalling 
the dorsal spine in length, while the lower one is reduced to a tooth, obsolete 
in some specimens. The lower lateral keel is distinct, terminating in the 
upper of the two spines at the infero-posterior angle. Below this another 
minutely denticulated submarginal keel runs from the branchiostegal spine 
backward to the lower and smaller spine of the infero-posterior angle of the 
carapace. The upper lateral keel is obsolete. 
The abdomen is rather slender, and is armed with a row of seven dorsal 
spines ; two of these occur on the first segment, two on the second, and 
one on each of the three following segments; the two spines on the second 
segment, together with the posterior spine of the first segment, are much 
7. 
