34 
T. V. HODGSON. 
endopodite has a broad base, a straight inner margin, the greater part of which is 
covered with fine setse. The inner margin tapers to a rounded apex, which is provided 
with long plumose setse. The exopodite is a little longer, much more delicate, ovoid 
in shape, fringed distally with long plumose setse. Where the exo- and endopodites 
do not overlap the endopodite is very stoutly built. 
The second pair, the endopodite, is similar to tjiat of the first, but quite without 
any thickening ; the exopodite is very much smaller, ovoid, and the plumose setse occur 
throughout the outer margin as well as distally. The appendix masculina is a narrow 
structure of almost uniform diameter ; it is slightly curved and enlarged near the 
distal end. On the inner side of this enlargement and on the outer side of the 
rounded extremity are series of very minute, backwardly-directed spines ; it is longer 
than the endopodite. The third pleopod is like the second, but the inner margin of 
the endopodite is slightly strengthened. 
The fourth pair has the exo- and endopodites subequal in size, heart-shaped, with 
a shallow notch near the apex ; they are thicker and more fleshy than the preceding ; 
they carry no setse. Both endo- and exopodites have an oblique fold in passing from 
the antero-exterior margin towards the postero-lateral margin. The fifth pleopod is 
rather larger than the preceding. The endopodite is more irregularly cordate and has 
an oblique fold. The exopodite is larger and two-jointed, the second joint being about 
one-fifth the length of the whole and terminates in a blunt but thickened point. 
Another similar thickening occurs about the middle of its inner border and close to 
it, and on the main joint is a further thickened knob. A ridge runs from this along 
the inner border of the first joint for some distance and passes straight on inside a 
lobe of the exopodite. 
A rather large number of specimens were taken at Cape Adare on February 24, 
1904, from the root of a large laminarian Lessonia grandifolia, taken in 17 fins. 
ANTARCTURUS. 
The genus Arcturus was established by Latreille in 1804, and since that time it 
has received a very large number of species, chiefly from the Southern Seas. Now, 
however, the genus is to be broken up. Dr. zur Strassen has begun the operation and 
separates the northern species which contain the type, from the tropical and southern 
forms on the ground that in the type species the mouth parts are concealed from a 
lateral view, and that the dactyli of the anterior pereiopoda are comparatively very 
small. In the southern species the mouth parts are distinctly visible from a lateral 
aspect, and the dactyli of the anterior pereiopoda are large. For these the genus 
Antarcturus is instituted, and this contains the greater number of species. It, is 
probable, however, that it is only a temporary delay in the further breaking up of the 
original genus, and if this alteration is to be carried on, minor characters, such as the 
