68 Mr. C. Spence Bate on a new Genus of Macrura. 
broad across the cardiac and branchial regions; but this can- 
not be clearly defined, as the laterally projecting tubercles 
are somewhat damaged either by the action of the gastric 
juices during the incarceration of the specimen in the dol- 
phin’s stomach or from manipulation afterwards in its dried 
condition. 
The anterior portion or frontal region is narrow and de- 
pressed, the central line being produced anteriorly into a 
small rostrum, on each side of which is a slight concavity 
or hollow space for the greater freedom of the movements of 
the ophthalmopoda and antennee. The antero-lateral angle is 
anteriorly projected downwards as a strong point or process 
that is slightly curved, and on the upper or dorsal surface 
is produced into a strong process or horn which is projected 
upwards and slightly curved backwards at an elevation higher 
than the median line of the gastric region, which lies as a 
plane between the two lateral prominences and separated 
from them by a deep and narrow fissure. The cardiacregion is 
surmounted by two large tubercles that are separated from each 
other longitudinally in the median line. Both lateral promi- 
nences are circular at base, tipped with small tubercles, and 
mammiform in appearance ; posterior to these on each side is a 
row of three tubercles continuous to the posterior margin of 
the carapace. On the outer or lateral side the branchial 
region 1s produced into large protuberances, the surfaces of 
which are not clearly distinguishable, from external injury; the 
lateral walls are curved inwards on the lower surface, leaving 
only a narrow space between them, in which lies the posterior 
portion of the pleon and the rhipidura or tail-fan. 
The pleon is narrow, smooth, and laterally compressed ; 
the telson tapers posteriorly and terminates in two processes, 
one at each postero-lateral angle, and on its inner margin 
bears a series of six sharp teeth which gradually increase in 
length, and the lobe is tipped with a smooth spine 0°5 
millim. long. The telson is also armed on each side with 
three small spines—one near the middle, a second halfway 
between the first and the posterior extremity, and the third 
rather nearer than halfway between the preceding and the 
posterior extremity. 
The carapace is about 9 millim. long. 
The pleon is about 6 millim. 
The telson is about 2 millim. 
The ophthalmopoda (PI. IX. fig. 1, a) are long and broad, 
the ophthalmus being large, pear-shaped, and projected upon 
a slender biarticulate peduncle. 
The first pair of antenne (4) are short, the first joint is 
