Febbuaet 25, 1916] 



SCIENCE 



281 



denee in the reader. Other species, as, for ex- 

 ample, P. Cyclops (von Linstow), P. nemeto- 

 soma (Leidy) and P. salvelina (Linton), are 

 given less space, such being, as a rule, records 

 of material that either did not admit of certain 

 identification, or at least were inadequately 

 described. Such species as P. amhloplites 

 (Leidy) and P. perplexus (LaEue), which are 

 American species and have been studied by the 

 author, are described in detail, and with such 

 discrimination that there should not be any 

 confusion in future identifications of these 

 forms. Comparative tables of selected char- 

 acters of Proteocephalid species are given. 

 Such tables are of peculiar value in the iden- 

 tification of such soft-bodied forms as cestodes 

 and trematodes, whose superficial appearance is 

 affected diversely by preserving fluids. Under 

 distribution it is of interest to note that am- 

 phibian Proteoeephalids are known only from 

 the two continents, North America and Aus- 

 tralia, while those of reptiles and fish are 

 known from all the continents. 



The following conclusions are of general 

 interest : 



1. A species of Proieocephalus may occur in 

 different host species of the same genus. Five 

 species are limited exclusively to various spe- 

 cies within the same host genus. 



2. A species may occur in the different gen- 

 era of the same family. 



3. A species may occur in the members of 

 closely allied genera, i. e., of the same order. 

 Four cases are known. 



4. A species may occur in families of very 

 wide relationship, %. e., of different orders. 

 There are two cases, of which one is doubtful. 



A further general statement is: The para- 

 sitic infestation of the host is determined by 

 the food eaten. 



A suggestive fact, pointing to a wide and 

 fruitful field of investigation, is indicated 

 when it is noted that in this monograph of 350 

 pages less than 2 are devoted to the life his- 

 tories of the Proteocephalidse, and these pages 

 are largely taken up with a discussion of prob- 

 able life histories. 



As to the relationship of the Proteoeephalids 

 to other cestodes, the author finds that struc- 



turally they are to be considered as being 

 closely allied to the Tetraphyllidse, while their 

 relationship to the Oyclophyllidae is distant. 

 The inclusion and long retention of the Proteo- 

 eephalids in the great genus Tcenia was due 

 to external features alone. 



The origin of the Proteoeephalids is dis- 

 cussed and the suggestion made that it may 

 have been some member of the family Lepisos- 

 teidse that is responsible for the introduction 

 of these cestodes into the fresh-water environ- 

 ment. 



A bibliography of 78 authors and 144 titles 

 is appended. These range in time from 1766 

 to 1912. Edwin Linton 



"Washington and Jeffeeson College, 

 Washington, Pa., 

 January 22, 1916 



SCIENTIFIC JOURNALS AND ARTICLES 



The opening (January) number of Vol. 17 

 of the Transactions of the American Mathe- 

 matical Society contains the following papers : 



W. F. Osgood : " On functions of several 

 complex variables." 



E. B. Van Vleck and F. H'Doubler: "A 

 study of certain functional equations for the 

 ^-functions." 



B. A. Bernstein : " A set of four independent 

 postulates for Boolean algebras." 



L. P. Eisenhart : " Transformations of sur- 

 faces Q, (second memoir)." 



E. J. Moulton : " On figures of equilibrium 

 of a rotating compressible fluid mass; certain 

 negative results." 



The February number (Vol. 22, No. 5) of 

 the Bulletin of the American Mathematical 

 Society contains : Report of the ninth regular 

 meeting of the Southwestern Section, by O. D. 

 Kellogg; " A note on the problem of Lagrange 

 in the calculus of variations," by G. A. Bliss; 

 " Concerning a non-metrical pseudo-archi- 

 medean axiom," by R. L. Moore; "A type of 

 singular points for a transformation of three 

 variables," by W. V. Lovitt ; Review of Golden- 

 ring's Die elementargeometrischen Konstruk- 

 tionen des regelmassigen Siebzehnecks, by R. 

 C. Archibald; " Shorter Notices; " Wentworth 

 and Smith's Plane Trigonometry and Tables 



