MUSEUM OF COMPARATIVE ZOOLOGY. 23 
The closing net of the “‘ Hirondelle ” for deep-sea pelagic work is a some- 
what complicated and expensive piece of apparatus,’ but appears to have 
worked well, although special data are not at hand regarding the exact 
depths of its working; and as is sufficiently clear, results obtained in 
the Mediterranean, or any ciosed sea like it, as the Baltic, or close to the 
shores of any mainland, cannot be correlated with those of the open sea, 
far from the disturbing factors at those localities. 
OBSERVATIONS ON THE PeELAGic Fauna By Dr. C. Cuun. 
The next experiments were those of Dr. Chun, who, under the aus- 
pices of the Naples Zodlogical Station, made an expedition to the Ponza 
Islands. Dr. Chun and the engineer Petersen applied to a tow-net an 
apparatus for closing it, similar to the propeller in use on our ther- 
mometers and water cups. Chun towed to a depth of 1,300 to 1,400 
meters, but never at any great distance from the mainland or from 
the islands of the Gulf of Naples, and came to the conclusion that the 
pelagic fauna existed all the way to the bottom.? 
In a notice of Chun’s memoir on the results of this expedition, I ques- 
tioned the conclusions to which he had arrived, and quote the following 
résumé from the American Journal of Science * : — 
“Unfortunately, this expedition, interesting as its results are, does 
little towards settling the subjects under discussion, because neither the 
distance from shore nor the depths investigated were great enough to elim- 
inate the disturbing effects of close proximity to land, as it was near the 
continental slope, on the very edge of which Dr. Chun trawled with the 
tow-net. The results are further vitiated from the fact that they have 
been carried on in a closed sea where the conditions of temperature are 
strikingly different from those of the Atlantic, and where at a depth of 
about 500 fathoms we find already the lowest temperatures of the deepest 
part of the Mediterranean. The minimum seasonal differences of tem- 
perature between that and the surface cannot be contrasted to oceanic 
conditions.” 
On his trip to the Canary Islands, his second pelagic fishing expedi- 
1 Compte-Rendu des Séances du Congrés Internat. de Zoologie, Paris, 1889, pp. 
133-159. 
2 Bibliotheca Zoologica. I. Die pelagische Thierwelt in grésseren Meerestiefen 
und ihre Beziehungen zu der Oberflichenfauna, 1887. 
3 A. Agassiz, in Am. Jour. of Science, Vol. XXXV. p. 421, May, 1888. 
