102 



SCIENCE 



[N. S. Vol. XXV. No. 629 



species formerly referred to this genus should 

 be placed in a group distinct from Hipparion.' 



A valuable paper of Professor Whitfield's 

 on ' Six New Species of Unios from the 

 Laramie Group,' attracts attention in this 

 volume, pointing as it does to a possible west- 

 ern metropolis and origination for fresh-water 

 shells of this family in the central and Mis- 

 sissippi basins. 



A new glyptodon from the lower Pleisto- 

 cene of Texas was described by Professor Os- 

 born, and possesses extreme interest. " It 

 proves to represent a new genus and species, 

 combining characters of several of the South 

 American forms of the Pleistocene and Mio- 

 cene periods." 



The Stone Expedition to Alaska in 1902 col- 

 lected 1,100 specimens of mammals, repre- 

 senting 43 species and subspecies, in which are 

 50 head of large game, and a series of 31 skulls 

 of the Kadiak bear. It was a remarkable col- 

 lection. Dr. Allen describes it, and among 

 its additions to existing species is to be noted 

 the Osborn caribou (B. oshorni Allen). Mr. 

 Barnum Brown describes a new genus of 

 ground sloth from the Pleistocene of Nebraska, 

 Mr. Beutenmiiller new insects, and Professor 

 Wheeler distinctly furnishes a new literary 

 and scientific interest in his careful studies 

 and speculations upon ants, amongst which 

 prominence should be given to his views upon 

 gynandromorphism in these insects. 



Vol. XX. of the Bulletin was character- 

 ized by the signal predominance of the papers 

 in ' Mammalogy, Vertebrate Paleontology and 

 Entomology.' It is impossible or unnecessary 

 to particularize. The articles were systematic 

 and descriptive; all possess the distinctive au- 

 thority of their writers in their several fields 

 of research, but two, of especial interest, claim 

 individual notice. The first is by Dr. Mat- 

 thew, on ' Two New Oligocene Camels,' from 

 which this conclusion may be quoted : 



In the Miocene the camels show increasing di- 

 vergence and variety of type, and their relation- 

 ship to the preceding and succeeding stages is far 

 from clear. While we have reason to believe that 

 the center of dispersion of the Camelidse was 

 somewhere on the North American continent, we 

 have no reason to believe that it was in the partic- 



ular regions from which our fossil species have 

 been obtained. 



The second is by Professor Osborn on the 

 great Cretaceous fish, Portheus molassus 

 Cape. It is preliminary and brief, but it 

 announced the possession by the museum of 

 a most remarkable and monstrous fossil fish 

 procured by Mr. Charles H. Sternberg in 1900 

 from near Elkada, Logan Co., Kansas. Pro- 

 fessor Wheeler included in this volume a 

 very readable and attractive paper on ' Social 

 Parasitism among Ants.' 



In volume XXI. two very important papers 

 from Dr. Hay are noticed in which that well- 

 known osteologist locks horns with European 

 authors, and discusses the origin and relation- 

 ships of the testudines. A paper admirable in 

 diction and beautifully illustrated is Chap- 

 man's ' Life History of the American Pla- 

 mingo.' Professor Wheeler contributes a dis- 

 cussional paper on ' An Interpretation of the 

 Slave-making Instincts in Ants,' which ia 

 somewhat varied in type from the ordinal 

 group of papers, and is very suggestive. The 

 remainder of the volume contains the valu- 

 able and learned studies of the naturalists, 

 whose papers have now for over twenty-six 

 years maintained the high standard of this 

 publication. L. P. Gratacap. 



Ameeican Museum of Natural Histobt. 



The Relation of Leaf Structure to Physical 

 Factors. By Edith S. Clements. Trans- 

 actions of the American. Microscopical So- 

 ciety, 1905, pp. 19 to 102. Published under 

 a grant from the Spencer-ToUes fund. 

 In studying the reaction of the plant to its 

 physical environment the leaf is a peculiarly 

 favorable subject, because of its ready response 

 to alterations in the environmental factors 

 and because of the clearness with which such 

 response is manifested in changes of structure. 

 A considerable literature on the relations of 

 leaf structure to environment has grown up 

 in Europe, based upon the vegetation of 

 northern Africa, tropical Asia, etc., as well as 

 of Europe. But the subject has received 

 comparatively little attention from North 

 American botanists, notwithstanding the fact 

 that our wide range of climate and conse- 



