364 Messrs. J. Wood-Mason and A. Alcock on 
In our youngest specimen it is short and porrect, scarcely 
extending beyond the second third of the length of the 
antennal scale, and being much shorter than the carapace. 
In a somewhat older specimen it is decidedly ascendant, 
though still straight, and longer—reaching to the apex of the 
antennal scale—though still much shorter than the carapace. 
In a still older specimen it has almost completely attained 
the length and the upward curvature it has in adolescent 
specimens, though it is still distinctly shorter than the cara- 
pace. It is as long or longer than the carapace in all our 
adolescent specimens of both sexes, except the two largest, 
and in these, which are males, it is slightly shorter than the 
carapace ; whence it may with some confidence be inferred 
that, asin A. eximia, A. Agasstzit, 8. 1. Smith, and A. an- 
gusta, Spence Bate, it does not surpass the antennal scale in 
fully developed males. It is from >" toothed, 
In all our specimens the eye is much as in Spence Bate’s 
figure of A. angusta, not as in his fig. 7, pl. exxvi., in which 
the so-called ocellus is represented as round and separate 
from the rest of the eye. 
It appears to us probable that A. angusta is the adult male 
of A. brachytelsonts, the difference between the two in the 
number of the rostral spines being explained by the loss of 
the apical spine of the lower series in the process of reduction 
of the rostrum from the adolescent to the adult condition in 
the former; and possible that A. brachytelsonis itself will 
prove to be identical with A. ea¢mda, since the former differs 
from the latter only in having one spine less on the inferior 
margin of the rostrum, and since Spence Bate includes 
amongst the specimens referred by him to the former mdivi- 
duals with the same number of spines as in the latter. 
42. Acanthephyra curtirostris, W.-M. 
Acanthephyra curtirostris, Wood-Mason, Ann. & Mag. Nat. Hist. (6) 
vil. p. 195, 3. 
@. Differs from the male only in its slightly more pro- 
duced rostrum. 
e189 
3 ¢. The rostrum is = -toothed. 
3. The telson bears 9-10 pairs of dorsal spinules and 5 
somewhat longer apical ones, the median of which is appa- 
rently fixed. 
