OCTOBEB 28, 1910] 



SCIENCE 



597 



The work does not attempt to straighten out 

 the great confusion arising from different 

 names having been bestowed on the hydroid 

 and medusa phases of the same species, and 

 vice versa, i. e., the same names given differ- 

 ent species and genera. While this is, of 

 course, to be regretted, the author is fully 

 justified in his statement (p. 3), "These and 

 many other cases of a similar nature interpose 

 a barrier to our attempt to invent a system 

 which includes all hydroids and medusae in its 

 embrace." The hopelessness of such an at- 

 tempt is realized when we see that two thirds 

 of the genera of Leptomedusie in which both 

 hydroid and medusa forms are known have 

 different names for the colonial and medusoid 

 phases in the life history of the same species. 



He has been careful, however, to give the 

 hydroid name, whenever it is known, in dis- 

 cussing each species, as well as a description, 

 and often figures, of each hydroid which is 

 known to produce medusae. 



The carefully prepared synonymies under 

 each genus and species is particularly valu- 

 able in pointing out the errors of previous 

 writers, as well as giving all names by which 

 the species or genus has been known ; e. g., 

 under " corynitis McCrady " he says : '• Non 

 Corynitis Murbach, non Corynitis Nutting, 

 non Corynitis Hargitt," thus correcting a 

 serious error which had been made by suc- 

 cessive writers. It is unfortunate, however, 

 that these synonymies are printed in such 

 small type as to be trying to the eyes when 

 they are studied for any considerable length 

 of time. 



The work is replete with interesting facts 

 concerning the embryological and experimen- 

 tal discoveries regarding the species dis- 

 cussed, including a very complete resume "of 

 all that is known through the investigations 

 of the numerous workers in this group. 



The author regards the Trachymedusse and 

 Leptomedusse as being transformed actinules, 

 and the Anthomedus® and Leptomedusse as 

 being formed on a different plan, with their 

 bells not homologous with those of the first- 

 named orders. A further discussion of this 

 exceedingly important point would have been 



much appreciated by Dr. Mayer's fellow 

 workers. 



In one respect the work could have been im- 

 proved. It seems to the reviewer that a pre- 

 liminary discussion of the morphology of the 

 group, or of the several orders, correspond- 

 ing in general to that given by Allman in his 

 " Gymnoblastic Hydroids " would have been 

 very helpful, especially to those interested in 

 the medusas but not familiar with the tech- 

 nical terms employed and the homologies of 

 the parts, particularly those homologies which 

 exist between the various parts of the hy- 

 dranth and medusa; and the various forms of 

 gonosome. 



There is also occasional inconsistency in 

 sometimes including and sometimes omitting 

 the name of the authority after the specific 

 name : e. g., " Steenstrupia rubra Forbes " and 

 " Steenstrupia aurata" (pp. 31, 35). 



The reviewer, however, so thoroughly ad- 

 mires this excellent piece of work that he finds 

 himself in no mood for criticism of small de- 

 tails. " Medusse of the World " is a monu- 

 mental work which will take the very first 

 rank and be a classic of which the Carnegie 

 Institution may well be proud, and for which 

 the author is to be heartily congratulated. 



C. C. Nutting 

 State Univebsity of Iowa 



Identification of the Commercial Dyestujfs. 

 By Professor Samuel Parsons Mulliken, 

 of the Massachusetts Institute of Technol- 

 ogy. New York, Jolm Wiley & Sons. 

 1910. 



This elaborate treatise has just appeared as 

 Vol. III., of the author's "Method for the 

 Identification of Pure Organic Compounds," 

 and represents an enormous amount of careful 

 and laborious investigation on the part of 

 Professor Mulliken and his assistants. They 

 present here careful records of ten or more 

 separate tests, some of them involving the 

 skillful use of the spectroscope, upon nearly 

 1,500 different dyestuffs; and the results of 

 these experiments have been expressed in the 

 form of elaborate analytical tables, by which, 



