682 The American Naturalıst. LJuly, 
4. The quadrivittatus group, consisting of (1) guadrivittatus, (2) 
T. luteiventris, (3) T. affinis, (4) T. neglectus, (5) T. borealis, (6) 
possibly also 7. graecis. ; 
5. The minimus group, consisting of (1) 7: minimus, (2) T. consobri- 
nus, (3) T. pictus. 
6. The frater group, consisting of (1) T. frater, (2) T. amænus. 
T. speciosus is a rather isolated species, more closely resembling 7. 
frater than any other form. T. asiaticus has no close affiliation with 
any of the American forms. 
A table of measurements, a ‘“‘key” giving the salient features of 
the various forms of Tamias, and a diagram indicating the status, re- 
lationships, and lines of probable intergradation, accompany the paper, 
and make it a complete exposition of the group considered up to date. 
PHYSIOLOGY. 
Functions of Central Nervous System of Invertebrates. 
—Steiner! endeavors to determine experimentally what ought to be 
regarded as the the brain of those invertebrates that possess a supra- 
cesophageal ganglion, cesophageal commissure, and ventral ganglia. 
He regards the brain as characterized by the presence of the general 
motor centre in connection with at least one of the nerves of the 
special senses. In the crustaceans (Astacus, Carcinus, and Maja) 
removal of one-half of the supra-cesophageal ganglion, or cutting of 
the cesophageal commissure, caused circular movements toward the un- 
injured side. This indicates the presence of the general motor centre 
in the ganglion, and since it also gives origin to the nerves of the higher 
senses, the author regards it as the brain of the crustaceans. Experi- 
ments on insects (Blatta, Blaps, Carabus, Geotrupes, Musca, Vespa, 
Pieris, Papilio), and on myriapods (Julus), gave similar results. In 
molluscs (Pterotrachea, Pleurobrachea, Aplysia) destruction of even the 
vhole £*the cnnra hs. 1 1: ar POET. o ti nts, but 
the latter ceased as soon as the pedal ganglion was destroyed. In 
Octopus, after destruction of the dorsal ganglion, the movements took 
place normally, but only after stimulation, never spontaneously. This 
ganglion hence appears to perform the part of a cerebrum instead of a 
whole brain, Among annelids (Ophelia, Eunice, Diopatra, Nephthys) 
cutting the cesophageal commissure caused disturbance of movement. 
1 Sitzber d. königl. Preuss. Akad. d. Wissensch. zu Berlin, 1890, IL, p. 39. Cf, 
Centralb. f. Physiologie, Bd. IV., p. 180, 1890. 
