94 General Notes. (January, : 
Mediterranean form. The principal cause of the beliefin the pri- ~ 
mordial distinctness of the two faunze has been the comparison of | 
the productions of the Mediterranean with those of the North sea, — 
British channel or Brittany ; instead of,as should have been the case, ~ 
with those of Portugal, Southern Spain, Morocco and Senegal, 
The animals of these regions are those that first migrated to the © 
Mediterranean, and as we become acquainted with the fauna of | 
these regions, we shall see the differences zodlogists have noticed 
between them gradually disappear.” 
When once fairly outside of the Straits of Gibraltar, the monot: — 
ony of the sea-bottom disappeared, sandy, pebbly and rocky areas” 
were met with; the nets, which in the Mediterranean prevented 
the dredge from filling instantly with mud at the spot where 1t- 
struck the bottom, became useless; and the temperature of the — 
depths, owing to sub-marine currents, lost the uniformity so chat- 
acteristic of those of the Mediterranean. oo 
As a consequence of these varied conditions the forms of ant 
mal life increased in individuals and numbers, but among them, — 
along the Portuguese coast, were found species heretofore con- 
sidered exclusively Mediterranean. r 
t the entrance of the Bay of Biscay from the south, a remark- 
able inequality in the ocean bed was met with. A few miles be | 
yond a sounding of 560 metres the astonishing depth of 4557 — 
EME EEIE eee TRE ee ee Pa ee A See Ne eT 
metres was found, and only thirteen miles further on bottom was — 
reached at 400 metres—an irregularity scarcely to be paralleled by — 
the highest chain of mountains. ay 
The greatest depth sounded in the Bay of Biscay was 5100 
metres, or about three and a quarter miles, and it was resolved to . 
attempt to use the dredge at this depth. The operation a | 
Desfosses, are destitute of a crystalline lens, although they ar 
vided with a retina. The blind subterranean fishes may 
followed by two arms on each side, the anterior largest of a 
The bell is transparent, its walls and lobes very contractile, ati 
its outer and inner surfaces covered with cilia, which are long 5 
_on the margins of the lateral lobes. The young Nemertines * 
eveloped in a folded position, within the lower and poste 
part of the larval envelope, and are distinctly segmented 
~LOPCO 
