1440 
THE VOYAGE OF H.M.S. CHALLENGER. 
Ke^emblance 
BETWEEN TOE 
Shallow-Water 
Marine Faunas 
OF Britain and 
T R isTAN DA Cun HA. 
Animals of High 
Northern and 
High Southern 
Latitudes. 
I’lMIM UK THE 
Northern and 
»utiiern Hemi- 
^PHEKF.«. 
shallow water iu the extra-tropical regions of the southern hemisphere were those 
about the Tristan da Cunha group. With reference to these dredgings and trawlings, 
Professor Wyville Thomson wrote in the Station-book at the time : “ From 150 to 
100 fathoms the dredge brought up a large quantity of specimens of all groups. . . . 
Altogether a mass of material much like what is found off the coast of England. , . , 
From 75 fathoms nearly the same things were got as in 60 fathoms, notably a profusion 
of Alcyouarians. These shallow-water dredgings around Tristan da Cunha gave a great 
iiraount of material, the fauna being very much of the same character as that of some- 
what shallower water in the north. The species seem in many cases to be identical, 
but this will require critical examination to determine.” ‘ 
The general similarity between the animals from the dredgings and trawlings in 
high southern latitudes and those from like positions in the high northern latitudes 
was the subject of frequent discussion among the naturalists during the whole of 
the southern cruise of the Challenger. The number of identical or nearly identical 
Mollusc shells in the Challenger collections from the deposits in 400 fathoms off the 
Azores, and off the south-eastern coasts of Australia, was especially remarkable. Again, 
the similarity, and in many cases identity, of species from high northern and high 
southern latitudes is frequently pointed out by the naturalists who have written the 
Zoological l\Iemoirs in the Challenger Report. This may be illustrated by the following 
extracts, dealing with distribution and development : — 
GCnther writes : “The fauna of Chili and Juan Fernandez might be described, without much exaggera- 
tion, as a mixture of European and New Zealand forms ; of the fishes mentioned here two being identical 
with, and four representative of, European species.” ^ Lycodes “ is represented in the Southern as well as 
Northern Hemisphere, but it would appear from the present state of our knowledge that the Antarctic species 
Jo not descend to so great a depth as the Arctic. Probably all of the latter will be found to reach beyond 
the vertical limit of 100 fathoms. . . . Two species only of Gymnelis are known: one [Gymnelis viridis^ 
from the Arctic Ocean, the other [^fTymnelis picta\ from the Straits of Magellan.”^ “The most striking 
character of the fauna [of the southern temperate zone] is the reappearance of types inhabiting the 
corrcsiKHiding latitudes of the northern hemisphere, and not found in the intervening tropical zone. This 
interrujition of the continuity in the geographical distribution of shore-fishes is exemplified by species as well 
as genera, for instance — Chinuera monstroHa, Galeus cams, Acanthias vulgaris, Acanthias blainvillii, Rhina 
squaiina, Ztut jaher, Lnphius jnsralorius, Centriscus scolopax, Engraulis cncrasicholus, Clupea sprattus. 
Conger vulgaris. Instances of genera are still more numerous — Cestracion, Spinax, Pristiop>homs, Raja; 
Callaidhias, PoUjprion, Ilidiigihrus, Cantharns, Box, Girdla, Pagellus, Chilodactylus, Sebustes, Aploactis, 
Agonus, L'qiidnpus, Cytltis, Psychrolulidx, Notacanthus ; Lycodes, Merluccius, Lotella, Phycis, Motella ; 
Aulopus; Urorampus, liolenognalhus ; Myxine. . . . The reappearance of so specialised a genus as Lycodes 
[in the Antarctic] is most remark.able.”^ 
IIerdman writes: “The di.scovery, so far south as Kerguelen Island, of a member of this genus 
[Auz/yrn], which lias been hitherto found only in the northern hemi.sphere, is very interesting. ... In the 
genus Bolh-nia, one sjiecies occurs in the extreme north, while the other two are from far south, the genus 
being unrepresenUrd in intennediate latitudes. ... In tlie genus Sfyela, all the species, with the exception 
' .S«e anU, ]i. 300. 
’ Zoo). CIia]l. Ez|>., i>t. Ivii. i>]>. 70, 81. 
* Zoo). Clinll. Exp., pt, vi. p. 23. 
* .Stiiily of Kisties, pp, 281, 290, Loudon, 1880. 
