1232 General Notes. | December, 
Ridgway also describes Cancroma zeledont, from Central America, 
and Rupornis gracilis, from Yucatan Steyneger describes 
(2. c.) a new species of tree-sparrow (Passer saturatus) from the 
Liu-kiu islands, José C. Zeledon contributes tothe Proc. U. S, 
Nat. Mus.,a list of the birds of Costa Rica, 692 species in all. 
L. M. Turner gives (} c., 233) a list ofthe birds of Labrador from 
Hudson strait to the Gulf of St. Lawrence, and west to 82° W. 
long., 764 species in all. 
Mammals—F.W. True (Proc. U. S. Nat. Mus., 1885, 95) de- 
scribes as new Phocena dalli, and reduces the previously describ- 
ed species of porpoise to three, viz: P. communis, P. lineata, and P. 
spinipinnis. In coloration, in the form of the head, and in the 
much larger number of vertebra, P. dalli approximates Lagen- 
orhynchus. A cordate area of white occupies the belly and lower 
half of the sides; the beak is shorter and the temporal -fossz 
smaller than in P. communis; the vertebræ are ninety-seven 
or ninety-eight in number, instead of sixty-six, as in communis, 
and the dorsal fin is concave on its posterior margin. 
Aleuts, according to W. H. Dall, recognize this species as distinct 
from the smaller P, vomerina (= communis ?). 
EMBRYOLOGY. 
THE DEVELOPMENT AND STRUCTURE OF MICROHYDRA RYDERI 
Potts.—The discovery and prolonged observation in the living 
state of this remarkable fresh-water ccelenterate, which is ob- 
viously allied to Hydra, is due to the painstaking care of Mr. 
Edward Potts, who found it adherent to stones to which fresh- © 
_ tions, prepared by Mr. Harold Wingate, from three individuals. 
Fortunately two of these series of sections, one a slide containing 
forty-two transverse, and another nine longitudinal sections, ena- 
bles me to make a very thorough comparison with the structure 
of Hydra as displayed in a series of sections of H. viridis and H. 
fusca, from both of which Microhydra differs not only in size 
but also in histological details as well as in its mode of devel- 
- opment. This singular organism also differs widely from the 
_ marine Protohydra leuckartii Greef, in being very much smaller, 
wen being an inhabitant of fresh water ; it also differs from Pro- 
2 erie in in its method of reproduction by gemmation from the 
side We body instead of fe transverse fission. In this last 
DC 
ey Vol. v, 1885, No. 123, in the accompanying cover sheets, called the Sci- 
lletin Pe om mader Se aS head of Recen po lesa el of Societies, the name 
ef we ot Eaei ons together with a brief gems of its structure 
| communication made by Mr. Potts at the meeting 
ences of Philadelphia, held ra 19, 1885. 
