622 THE AMERICAN NATURALIST. (VoL. XXXIII. 
the interaction of the nervous elements. The author concludes that 
our present knowledge on this subject is too scanty to afford any 
sound basis for generalizations. 
The fourth number of Volume II of the American Journal of Physi- 
ology contains the following papers: “The Mechanism of the Motor 
Reactions of Paramecium,” by H. S. Jennings; ‘“* On Absorption 
from the Peritoneal Cavity,” by L. B. Mendel; “The Origin of the 
‘Traube’ Waves,” by H. C. Wood, Jr.; “ Laws of Chemotaxis in 
Paramecium,” by H. S. Jennings; and “The Chemistry of the 
Melanins,” by W. Jones. 
The hearts of several species of lungless salamanders were studied 
several years ago by Hopkins, who reported the absence of pulmo- 
nary veins, but the presence of an auricular septum. H. L. Bruner 
(Anat. Anzeiger, Bd. XV, No 22) has reinvestigated the subject, and 
finds no auricular septum present, but that the sinu-atrial valve is 
so placed as to be easily mistaken for such a septum, an error which 
he believes Hopkins to have fallen into. 
Dr. Carlgren thinks (Zool. Anz., Vol. XXII, p. 102) that the 
Branchiocerianthus urceolus, recently described by Mark, is a hydroid 
near Corymorpha. 
Walter May contributes an excellent review of the classification 
and distribution of the Alcyonoid polyps to the /enazsche Zeitschrift, 
Bd. XXXIII. Many new species are described. : 
In his “ Revision of the Squirrels of Mexico and Central America ” 
(Proc. Wash. Acad, Sci., Vol. I, pp. 15-106), Nelson recognizes forty- 
three species and subspecies. 
“North American Fauna No. 14,” issued by the Biological Survey 
of the United States Department of Agriculture, contains an account 
of the Natural History of the Tres Marias Islands, situated in the 
Pacific Ocean, not far from the Mexican coast. The mammals, 
birds, reptiles, crustaceans, and plants are dealt with, and the report 
concludes with a bibliography of these islands. 
Cyathocephalus truncatus is the only known cestode characterized 
by the transformation of the entire scolex into a single bothrium. 
To this genus Riggenbach has just added a second species, C. cati- 
natus, from Solea vulgaris. 
Scolex abnormalities are very common in Cænurus serialis, accord- 
ing to Railliet, C. Æ. Soc. de Biol, Jan. 21, 1899, who found in a 
