7 34 General Notes. [August, 
contraction, and (4) inhibitory, interrupting the contraction and 
effecting relaxation. The motor’ nerves of each muscle spring 
from the nearest ganglion; but all the inhibitory fibers originate 
in the anterior ganglia. The latter pass to the anterior adductor 
by the short nerve-branches which pass to it from the anterior 
ganglia, They reach the posterior muscle through the connec- 
tives. The posterior ganglion thus functions as motor center for 
the posterior adductor; and the anterior ganglia act similarly on 
the anterior adductor. The motor cells of the ganglia on either 
side may be stimulated to activity, either by peripheral nerve- 
fibers (of the mantle or gills) or by certain fibers of the connec- 
tives. The anterior ganglia are able to produce relaxation in 
either anterior or posterior adductors.” 
AsyssaL DECAPOD CRUSTACEA OF THE NORTH ATLANTIC.—Pro- 
fessor S. J. Smith reports in the Annals and Magazine of Natural 
History (1886, 187) on the species collected by the Albatross. 
found at depths below 1000 fathoms. The first question whic 
arises is, which of these actually inhabited the bottom? Fifteen 
' of them—that is the two Brachyura, the seven Anomura, the 
_ Eryontids, Crangonids and Glyphocrangonide among the Mac- 
rura—are unquestionably inhabitants of the bottom. It 1s doubt- 
ful whether those that are here grouped together as Miersiide 
` istic forms taken in trawling at great depths, while the structure, 
= butto be free-swimming; the eight species o 
-~ arein the list are undoubtedly free-swimming forms not confined 
_ to the immediate region of the bottom, but their relatively small 
_ eyes and well-developed ocular papillae indicate that they are 
__ deep-water if not abyssal species. : 
_ The author provisionally groups the species into four classes : 
I. Species inhabiting the bottom or its immediate neighborbooi 
_ 2. Species probably not confined to the immediate neighborho 
of the bottom, but showing structural evidence of phe 
abyssal depths. 3. Doubtful, but probably inhabiting abyss% 
depths. 4. Species probably not inhabiting abyssal depths. 
of the species are remarkable for their large $176, — 
that are very small; many are large members 0 
