1892.] . Zoology. 781 
connection with Cope’s discovery of the mammalian condition of the 
limbs in the Theramorpha is strong evidence against the derivation of 
the Mammalia from the Batrachia; both Mammals and Sauropsida 
must have come from an ancestor with the phalangeal formula 2, 3, 4, 
5, 4, or more. 
Twisting of the Umbilical Cord.—In man and many mam- 
mals the umbilical cord is twisted but the twisting may be either right 
or left handed and the number of turns may vary. To explain this twist- 
ing several hypotheses have been advanced, the last being that of Prof. 
F. J. Allen. The twisting consists in the twining of the two arteries 
about the single vein of the cord, and this involves an increase in 
length of the arteries greater than that of the vein. To test this Allen 
devised a model of rubber tubes and cord and found that the hypoth- 
esis was fully supported by the model. It is not easy to see what is 
the gain to either foetus or mother by this twisting. 
General Notes—Lower Invertebrates.—Dr. R. von Lenden- 
feld publishes a preliminary arrangement of the calcareous sponges. 
The work is based upon the labors of Haeckel and Poléjaeff. Twenty- 
one genera are recognized. 
Arthropoda.—Emile Deschamps claims‘ that the recently estab- 
lished genus Abacola of Prof. C. L. Edwards is synonymous with Thy- 
opsyllus of Brady. 
Dr. Paul Marshal describes a hermit crab (Pagurus striatus) which 
he found inhabiting a left-handed shell of Neptunea contraria. The 
abdomen of the individual was normal and showed the same lack of 
symmetry as its fellows, and on trial was found to hold itself equally 
well in both dextral and sinistral shells. 
E. A. Birge publishes’ a list of 64 species of Cladoceran Crustacea 
from Madison, Wisc. Latonopsis occidentalis and Alona lepida are 
described as new. A new species of Moina is indicated but not 
described. 
Vertebrates.—C. K. Averill catalogues for the Bridgeport Scien- 
tific Society 246 species of birds found in the vicinity of Bridgeport, 
nn. 
‘Jour. Anat. and Phys., xxvi, 300, 1892. 
5Stz. Akad. Wien., Bd. c. Abth. 1, p. 4, 1891. 
6Bull. Soc. Zool. France, xvii, p- 68, 1892. 
Trans. Wisc. Acad. Sci., viii, 1892. 
