I loo The American Naturalist. [December, 
Frontals not excluded from orbit ; plastron united to carapace by 
ligament, and more or less distinctly divided in the adult into two 
lobes between hyo- and hypoplastra ; entoplastron not intersected by 
the humero-pectoral suture. Rib-heads very long, as in Chelydra. 
Type, Emydoidea blandingii, Holb. Deirochelys Ag. (name only.) 
Dirochelys Ag. 
Frontals not excluded from orbit ; plastron united to carapace by 
suture, not divided into movable lobes ; entoplastron not intersected 
by the humero-pectoral suture. Rib-heads very long, as in Chelydra. 
Type : Dirochelys reticularia, Latr. Clemmys is in the same relation 
to Emys, as Dirochelys to Emydoidea. 
It is clear that Emys has developed from Clemmys and Emydoidea 
from Dirochelys ; the ligamentous connection between plastron and 
carapace is secondary. — G. Baur. 
Habitat of Xantusia riversiana Cope. — The locality from 
whence the specimen came that Prof. E. D. Cope described has not 
hitherto been recorded ; and I now add that information. It was 
found upon San Nicolas Island, the westward island of the Santa Bar- 
bara group California. I have recently received some examples of 
this lizard from Catalina Island, a larger island of the same group. 
The lizards contrast in size as do the islands, the larger lizards from 
the larger island. — J. J. Rivers, University of California, April 24th, 
i8go. 
Zoological News.— General.— Students who wish to understand 
the present stage of the study of cell division and its relations to im- 
pregnation, heredity, etc., will find an admirable resume by Waldeyer 
translated in the Quarterly Journal of Microscopical Science for July 
and December, 1889. It being itself a summary, no abstract can do it 
Coelenterata.— In the Bergens Museums Aarsberetning for 1888 
[1889], Dr. D. C. Danielssen gives an anatomical description of 
Cerianthus borealis, which he recognizes as destinct from C. lloydii. 
Fisher^ states that in Cerianthus the number of tentacles is always 
odd, the unpaired tentacles being on the ventral side. 
Echinoderms. — In a list of invertebrates of the Western fiords of 
Norway^"* Grieg describes and figures as new Cucumaria r, 
9 Bull. Zool. Soc. France, XIV. 
i» Bergens Museums Aarsberet. for 1888 [1889.] 
