242 The American Naturalist. [March, 
I note the description of one new species, Anculosa harpethensis Pilsbry. 
It is distinguished from A. subglobosa Say. by its globular form and the 
angulation at the base of the columella; “ face of columella concave, a 
projecting angle at union of columellar and basal lips.” 
MamMata.—The mammals collected by Dr. A. Donaldson Smith 
during his expedition to Lake Rudolf, Africa, representing 50 genera 
and 77 species, 7 of which are new, have been described in the Pro- 
ceedings of the Academy of Natural Science of Philadelphia (pp. 517- 
546) by Mr. 8. N. Rhoads. 
EMBRYOLOGY.’ 
Spinning Powers of Certain Eggs.—It is well known that the 
protoplasm of many one-celled animals may flow out as excessively 
delicate threads of living matter that exhibit remarkable currents and 
contractile phenomena. Something similar to these filose “ pseudo- 
podia” is met with in certain cells of many-celled animals, as in the 
pigment cells of the retina, ete. In a recent paper by Gwendolen 
Foulke Andrews’ it is claimed that the eggs of star-fish and sea-urchins 
form very much the same sort of ee pseudopodial filaments as are 
produced in those one-celled animals. 
These thread-like processes are “spun” out from the protoplasm of 
the egg in such exceedingly delicate filaments that they have escaped 
notice and have now been revealed only with good lenses and excep- 
tional optic resources. 
From the elevation of the egg’s surface that meets the sperm a “ tuft” 
of fine threads is spun out ; the whole surface of the eggs spins out rm 
threads to make the egg membrane ; the egg spins during cleavage; 1 
spins out the cilia that move the blastula: ; it spins filaments across fy 
cleavage cavity and from one germ-layer to another in the gastrula ; ; 
and the polar bodies spin like the rest of the egg. 
These threads spun out are flowing material that branches, anasto- 
moses, shows currents and other phenomena very much as do the pseudo- 
podial filaments of such one-celled animals as Gromia. 
1 Edited by E. A. rnae Baltimore, Md., to whom abstracts, reviews and 
preliminary notes may 
2 Journal of o, Sein 1897, pps. 367-389. 
