654 



SCIENCE. 



[X. S. Vol. XXI. Xo. 539. 



then the custodian of the fish collection of the 

 British Museum as well as ' keeper of the 

 zoological department.' His successor as 

 custodian of the fishes, Dr. George A. 

 Boulenger, is one of the authors of a new 

 work covering practically the same ground as 

 Dr. Giinther's. The new work labors under 

 the disadvantage of having no real descriptive 

 title-page. On a bastard title-page it is 

 designated as ' The Cambridge Natural His- 

 tory — Volume VII.,' and on the true title-page 

 it has the following legends apportioned and 

 punctuated as here represented. 



Hemichordata 



By S. F. Harmer, [etc.]. 



ASCIDIANS AND AmPHIOXUS 



By W. A. Herdman, [etc.]. 

 Fishes (Exclusive of the Systematic Account of 

 Teleostei ) 

 By T. W. Bridge, [etc.]. 

 Fishes (Systematic Account of the Teleostei) 

 By G. A. Boulenger, [etc.]. 



London 

 Macmillan and Co., Limited 

 New York: The Macmillan Company 

 1904 



We are thus compelled to refer to it as the 

 Cambridge Natural History, Volume VII. 



The new work, in line with modern concepts 

 respecting the vertebrates or chordates, in- 

 cludes not only the lower types of the verte- 

 brates of the old naturalists, but also the 

 Hemichordata and Urochordata or Tunicates. 

 The old class of fishes of the ' Introduction ' 

 is replaced by the 'three classes for more than 

 a generation past adopted in America, that 

 is, the ' Cephalochordata ' (Leptocardians), 

 the ' Cyclostomata ' (Marsipobranchs) and 

 the 'Pisces' (Teleostomes or fishes proper). 



It may be noted that the names Hemi- 

 chordata, Urochordata and Cephalochordata 

 are given as terms of subphyla and not as 

 class names. The constituents of the first, 

 for Dr. Harmer, are the ' orders ' Enterop- 

 neusta, Pterobranchia and Phoronidea, each 

 of which has been considered by some as a 

 class, or, at least, far removed from the others ; 

 the second is universally known as the class 

 of Tunicates or Ascidians, the third as the 

 class Leptocardians. The three subphyla 



thus named are succeeded by another sub- 

 phylum — ' IV. Craniata,' which is divided 

 into two classes : ' Class Cyclostomata,' gen- 

 erally called Marsipobranchs or Myzonts, and 

 ' Class Pisces,' including the Selachians and 

 true fishes, or Teleostomes. 



II. 



The three ' orders ' aggregated as ' Hemi- 

 chordata ' can not be considered to have been 

 proved beyond all cavil either to be closely 

 related or to be true Chordata. The student 

 may find a summary of the arguments respect- 

 ing the ' afiinities of the Hemichordata ' at the 

 end of the chapter on the group (pp. 30-.32). 

 It is not long since almost all the known 

 species of Enteropneusta were supposed to be 

 referable to one genus — Balanoglossus. Now 

 they are distributed among three families and 

 the oldest of them appears under the guise of 

 Ptychoderidae. 



III. 



The ' Urochordata ' or Tunicata have been 

 elaborated in excellent style by the eminent 

 monographer of the ' class ' (Professor Herd- 

 man), who has long been known in connection 

 with those animals. In spite of the many 

 different changes and systems that have been 

 proposed by others while he has been actively 

 engaged on the group, he retains practically 

 unchanged the system he employed in the 

 Encyclopaedia Britannica (1888) and the 

 Journal of the Linn^an Society (1891). It 

 is noteworthy, too, that the name Cynthia is 

 still kept, although there is a well-known 

 genus of Fabricius (1808) so termed long 

 before Savigny's genus (1827) was established. 

 That the retention was deliberate and in spite 

 of the facts is evident from a note to the 

 same in the Journal of the Linnwan Society 

 (23, 576), where the substitute ' Halocynthia, 

 Verrill, is [declared to be] merely a synonym.' 



IV. 



The main structural features of the 

 ' Cephalochordata ' are passed under review 

 in an able manner and the latest sources of 

 information made, use of. The classification 

 is derived by Professor Herdman from Mr. 

 Walter Tattersall; that author is evidently 



