Amphipoda with notes on a species of Isopoda. 443 
Since 1906 the following new species have been attributed to the genus : A. hrevicor- 
nis, Chevreux, A. longicornis, Chevreux, A. calceolata, Chilton, and A. aucklandicus , 
Walker, while a fifth species, originally described by Stebbing as A tylopsis magellanica 
and transferred later by him to the genus Pontogeneia, was also referred to Atyloides by 
Chilton. Barnard (1916) has, however, shown that A. magellanica is the same species 
as Pontogeneia capensis (Dana) and is in realit}" a species of Paramoera. 
The germs Atyloides therefore at the moment contains seven species. According 
to Stebbing (1906) the genus is distinguished from Paramoera only by having the first 
antenna longer than the second instead of shorter and both genera are distinguished 
from all the others in the family by having a small one- jointed accessory flagellum to 
the first antenna. Of the seven species still retained in Atyloides, A. brevicornis and 
A. longicornis have no accessory flagellum and in both species the second antenna is 
longer than the first. It is impossible fromx the published descriptions to define the 
condition in respect to these characters in A. calceolata and A. aucklandicus. So that 
only three species, A. gahrieli, A. fontana and A. serraticauda conform to the original 
generic definition. 
Apart from the question as to whether Atyloides is not in reality a synonym of 
Paramoera, it will be seen that a good deal of confusion and uncertainty exists among 
the genera and species of this family. We may endorse Chilton's remarks that " in 
this family of Amphipods particularly there has been an unnecessary multiplication 
of genera, and consequently some characters have been introduced into the generic 
descriptions which are subject to individual variation." 
Into this confusion it does not seem opportune to introduce new generic names. 
I have therefore referred the new species described below to the genus Atyloides 
because it seems to me to be clearly congeneric with A. gahrieli and A. fontana and 
possibly with A. aucklandicus, Chilton, 1909, which is doubtfully the same as A. 
aucklandicus, W alker. 
Atyloides japonica, n. sp. 
[PI. XIX, figs. 13-19.] 
Locality. — Small torrent in hills behind Komatsu on Lake Biwa, 28-X-15, two 
specimens, 7 mm. 
Description. — Body smooth, without ridges, carinae or spines but with a few 
very short, scattered setae on the dorsal surface. First four coxal plates deeper than 
their respective segments, with a few short setae on their lower margins, first two 
not expanded distaliy, fourth not quite as broad as deep, excavated posteriorly. 
Third segment of the pleon having the posterior margin with 6-7 slight crenulations, 
a seta in each notch, lower posterior angle only very slightly produced, lower margin 
with three setae. Eyes large, at least half as deep as the head, reniform in shape, 
pigment black. 
First antenna (pi. XIX, fig. 13) about half as long as the body, first joint of the 
peduncle slightly longer and stouter than the second, third joint about two-thirds of 
the length of the second, flagellum composed of about 40 joints, accessory flagellum 
