732 General Notes. [August 
O. W. Oestlund publishes, in the Fourteenth Annual Report of 
the Geological and Natural History Survey of Minnesota, a list 
of the Aphididæ of that State, with descriptions ofa number of 
new species. The Entomological Society of Washington 
have issued, in a pamphlet of thirty-two pages, the first number of 
its Proceedings, which contains some interesting notes. f 
ZOOLOGY. 
GEOGRAPHICAL DISTRIBUTION OF PELAGIC MARINE ANIMALS.— 
Herr C. Chur (Zool. Anzeiger, p. 35) ascribes the wide distribu- 
tion of pelagic forms to four causes; they are of great geologi- 
cal age, and existed long before the elevation of the continents, 
while the appearance of the latter has given rise to currents 
which are of great significance in distribution ; they are provided 
with powerful locomotor organs; they or their germs may be- 
come attached to powerful swimmers, wood, or the feet of swim- 
ming birds; and lastly, they are aided by the wind, for when 
floating on the water they offer a broad surface. 
The author then proceeds to discuss the results of recent ob- 
servations which confirm the idea just enunciated; as pror“ 
es- 
the localization of Ccelenterata are explained b 
chitinous shell of the one, and the delicacy of the tissues of the 
other set of forms; at the same time, some ccelenterate spec! 
are very widely distributed. 
: tissues subjected to high pressures (100-400 atmospheres), and 
he fi af es the tissues. 
‘It is not yet certain whether this is due to water directly entering, 
_ or whether it combines with the albuminoids, and, atter the re- 
_ moval of the pressure, escapes and infiltrates the tissues. —/ ourn. 
Roy. Micr. Soc., June, 1886. 
_ Swett Formation 1N Brvatve Morrusks.—Dr. F. Müller Ls 
_ scribes the mode of shell formation in Lamellibranchiata. 2 
_ investigations relate chiefly to Anodonta, Unio and yae 
which chipped-off edges and sections were studied. The gece- 
_ cification was effected by means of dilute chromic acid; eee 
_ Mine was used for staining, and celloidin was found to be the S 
satisfactory imbedding material. rile 
_ The general result of Dr. Miiller’s research is to cornea a 
Mathusius in his account of the shell-growth by intussusceptt A 
ad not by secretion. He does not, however, exclude the pos?’ 
