398 A HISTORY OF RECENT CRUSTACEA 
this was removed from the fossil genus and twice renamed 
as Serolis Brongniartiana and as Serolis trilobitoides. Bed- 
dard considers it to be perhaps the same as Studer’s Serolis 
cornuta from the Crozets and Kerguelen. The distribution 
of the genus is rather peculiar, for though the type, first 
reported from Tierra del Fuego, is said by Leach to occur 
also on the coast of Senegal, and Serolis carinata, Locking- 
ton, has been recently described from California, all the 
other species belong to the Southern hemisphere. The 
shallow-water species do not even extend north of latitude 
30° S., and though some of the deep-water species approach 
the equator, none of them pass to the north of it. Serolis 
necera, Beddard, was dredged up from a depth of 2,040 
fathoms, and Serolis Bromleyana, v. Willemoes Suhm, 
from the slightly smaller depth of 1,975 fathoms. The 
latter somewhat exceeds the former species in size, and is 
the largest in the genus. ‘The male is more than two 
inches long and more than two inches broad, and, if the 
length is reckoned not along the central line but from the 
rostrum to the end of the greatly produced sixth side- 
plate, it exceeds three inches. All the deep-sea species 
except Serolis antarctica, Beddard, agree in having these 
side-plates greatly produced, especially in the male. The 
Australian Serolis minuta, Beddard, only a sixth of an inch 
in length and in breadth, is the smallest species known. 
Five other species belonging to Australia form a con- 
nected group, in which the dorsal portion of the sixth 
pereeon-segment is extremely narrow, and that of the 
seventh is either absent or fused with the first of the pleon. 
In these characters they agree only with Serolis minuta, 
and are separated from that by having the side-plates of 
the pleon undeveloped. These Australian species are 
named australiensis, elongata, pallida, longicaudata, by Bed- 
dard, accompanying the earlier tuberculata of Grube. ‘The 
island of Kerguelen, so richly supplied with sessile-eyed 
Crustacea, has three species, Serolis cornuta, Studer, Serolis 
septemcarinata, Miers, and Serolis latifrons, White. 
Mr. Beddard finds that the deep-sea species are distin- 
guished in an important manner from those of shallow 
