EUPHAUSIACEA. 295 
THE DISTRIBUTION OF THE EUPHAUSIACEA. 
As already stated, the Agassiz Expedition 1904-1905 in the tropical and 
subtropical East Pacific secured thirty-nine species of the order Euphausiacea, 
thus a little more than half of the species known from all Oceans together. 
Among these thirty-nine species nineteen are at present known both from the 
Atlantic and from the Indian Ocean, eight from the Atlantic, but not from the 
Indian Ocean, five from the Indian Ocean (in the main from the Indian Archi- 
pelago) but not from the Atlantic; thus thirty-two of the thirty-nine of the 
species enumerated here from the East Pacific are known from at least one of 
the two other great Oceans. And I think that in no other order of Invertebrates 
82 p. ec. of the species known from the warm area of the East Pacific are also 
known either from one of the two other Oceans or from both! Seven species 
remain; among these one, viz. Huphausia gibba G. O. 8., is also known from 
the West Pacific (between Api and Cape York), and a second, H. pacifica H. J. H. 
is widely distributed in the North Pacific and has been taken several times 
near Japan and Corea. Deducting these forms the following five species: — 
Nyctiphanes simplex H. J. H., Euphausia eximia H. J. H., EH. distinguenda 
H. J. H., #. lamelligera H. J. H., and EH. mucronata G. O. 8. are known only 
from the East Pacific, but one among them /. mucronata has also been captured 
off Chile, thus more southwards, and a second, Nyctiphanes simplex, is known 
from the Gulf of California and another location at Lat. 353° N. Three species 
remain hitherto not known to me from any Station outside the area explored 
in 1904-1905! 
As to the distribution within the area explored in 1904-1905 of the species 
taken at numerous localities I do not venture to say a great deal; an investi- 
gation of this kind must be connected with a detailed study of currents and tem- 
peratures. For the majority of the species in question I have in the passage on 
distribution pointed out the limits of the occurrence within the area explored, 
but I do not venture to attempt a more general treatment. Only one interest- 
ing detail I may call attention to. When two closely allied species, as Huphausia 
diomedeae Ortm. and FH. mutica H. J. H., Nematoscelis microps G. O. S. and N. 
gracilis H. J. H., were both taken at numerous Stations, they were only taken 
together at some few Stations, and in one part of the area one of such two allied 
species was very common but quite wanting in another part, while the second 
species, which was absent in the first part, was common in the other. 
Our knowledge of the bathymetrical occurrence and distribution is rather 
