102 MR. F, E. BEDDARD ON ISOPODA COLLECTED [Feb. 2, 
seventh thoracic segment and the abdominal shield is a narrow 
free abdominal segment, which is ridged like the posterior segments 
of the thorax. The abdominal shield is almost circular in its 
outline anteriorly ; posteriorly it terminates in a triangular-pointed 
extremity ; the posterior region is slightly serrated. 
Kerguelen, 120 fathoms. 
2, PLEUROGONIUM SERRATUM, N. sp. 
This species, like the last, is represented by a single female example 
measuring 3 millim. in length. 
The head is small and almost enclosed by the following segment 
of the thorax; the frontal margin is straighter than in the last 
species, and the articulation of the antenne is not so near to the 
posterior boundary of the head; the hinder margin of the semi- 
circular notch which lodges the antenne is prolonged outwards into 
a longish pointed process, which extends laterally nearly as far as 
the epimeron of the first thoracic segment. The thoracic segments 
are so like the last species that no special description is needed. The 
most characteristic and obvious difference between the two species is in 
the abdominal shield, which has, however, the same general shape in 
P. serratum as in P. albidum; in the former species the lateral 
margin as far back as the articulation of the uropoda is strongly 
serrated ; there is no trace of any such serrations in P. albidum 
except along the posterior extremity of the caudal shield behind the 
uropoda, in which situation they are absent in P. serratum. 
Kerguelen, 120 fathoms. 
3. PLEUROGONIUM MINUTUM, 0. sp. 
The third new species of this genus is represented by a single 
female example, dredged off Tristan da Cunha. It measures about 
1 millim. in length. 
The general shape of the body is like that of the other species. 
The epimera of the thoracic segments are not prolonged into spines 
as in the last two species, but are rounded in the four most anterior 
segments and truncated in the posterior thoracic segments. The 
abdominal shield is oval, tapering posteriorly ; anteriorly the margins 
of the abdominal shield are serrated, but the serrations are not nearly 
so marked, nor do they extend over so great an area as in P. serratum. 
In the two last species the antennz are twice the length of the 
antennules; in the present species they are longer, but only half 
as long again: in this respect therefore Pleurogontum minutum is 
more typical, that is to say it agrees more closely with the northern 
forms described by Sars. 
Off Tristan da Cunha, 100-150 fathoms. 
ACANTHOMUNNA, nov. gen. * 
This genus is like Munna in outward form, and is furnished with 
a pair of eyes elevated on stalks as in that genus ; the thoracic limbs 
are entirely like those of Munna except that they terminate in a 
