586 The American Naturalist. (June, 
New York Academy of Sciences.—April 10, 1893.—Biologi- 
cal Section—H. F. Osborn, on “ The Evolution of Teeth in Mammalia 
in its Bearing Upon the Problem of Phylogeny,” reviewed the recent 
researches and theories of Kükenthal, Röse and Taeker upon the forma- 
tion and succession of the dental series in mammalia, and pointed out 
that, especially in marsupials, cetaceans and edentates (with other 
placentalia) the existence of two series of teeth was now abundantly 
proven, as well as the fact that Homodynamous forms were derived from 
early Heterodont. He then showed that recent discoveries demonstra- 
ted that in marsupials, teeth of the second series might be interposed in 
the first series—to explain the typical dentition of such forms as Didel- 
phys. This transposition enables a comparison of dentition of mar- 
supials with that of Jurassic mammalia (=i, $, c, t, p, 4, m, $). It 
was further noted that the triconodont type (as Amphilestes) was 
probably the hypothetical point of divergence of placental mammalia. 
As to the form of crowns, the theory (Kükenthal-Röse) that complex 
mammalian types were made by concrescence of simple reptilian 
cusps was upon the evidence of the Jurassic mammalia shown unten- 
able, as well as the converse theory that cetaceans have derived their 
homodynamous form by the splitting of the cusps of triconodont. 
Bashford Dean, in “ Contributions to the Anatomy of Diniththys,” 
correlated the parts of this Devon-Lower Carboniferous Arthrodiran to 
those of Coccosteus. Notes were made upon the (1) disposition and 
character of the lateral line organs, (2) pineal foramen, (3) nasal cap- 
sules, (4) dentary plates (homologies), (5) ginglymoid articulation of 
lateral shoulder plates, (6) character of shagreen, (7) probable disposi- 
tion of paired and unpaired fins. 
N. L. Britton presented a “Note on the Genus Lechea.” This 
genus of Cistinee is entirely American, and from the investigations of 
Mr. Wm. H. Leggett and Dr. Britton appears to consist of about four- 
teen species. 
Natural Science Association of Staten Island.—March 18. | o 
—Mr. Wm. T. Davis exhibited specimens of the Leopard Moth and 
read the following communication : , 
On the 23d of June, 1888, I found on the sidewalk, under & partly 
decayed white maple on Fort Hill, a large white and black moth that 
was rendered helpless by having one of its fore wings broken in two 
_ It was not until last year, when Col. Nicholas Pike’s article and — 
accompanying figures on the ravages of the Leopard Moth—Zeuzer@ 
esculi (Linn.)—in Brooklyn, appeared in “ Insect Life,” that the moth 
