TECHNICAL NOTES AND BIBLIOGRAPHY 233 



'fit' each other, even as now, but whether for better 

 or for worse from man's point of view is a subject that 

 must be left to speculation. 



Confusion with respect to the origin of the vertebrates 

 has crystallized in the classification of the Vertebrata 

 (over 25,000 species) as a subphylum of the phylum 

 Chordata, the three other subphyla in this category be- 

 ing the numerically insignificant Hemichordata (perhaps 

 50 species), of which the worm Balanoglossus had held 

 greatest attention, the Urochordata (about 1400 spe- 

 cies), which includes the tunica tes or ascidians, and the 

 Cephalochordata (about 25 species) , of which the lance- 

 let, Amphioxus, is the biologists' ideal, which *if it hadn't 

 existed, would have had to be invented,' as Neal and 

 Rand say {38, p. 664}. This imposing classification arises 

 from certain parallels in embryology or adult anatomy, 

 and notably from the presence of 'gill arches' at some 

 stage of development, and of a stifFened rod or noto- 

 chord extending down part or the whole of the animal's 

 body, the last supplying the character from which the 

 term 'chordate' is derived. None of these throws any 

 hght on the origin or structure of the protovertebrate. 

 The erection of the phylum Chordata to include the 

 balanoglossids, tunicates, and Amphioxus along with 

 the vertebrates is a taxonomic tour de force which gains 

 nothing, and loses much, and it would be better to rele- 

 gate the first three to an appendix well removed from 

 the Vertebrata and entitled 'Mysterious Creatures of Un- 

 determined Affinities.' As Neal and Rand conclude, *The 

 Chordata clue seems to lead us into a blind alley out of 

 which the most promising exit is the way back.' Those 

 interested in the origin of the vertebrates will read Ber- 

 rill's recent book {28} with interest. 



Two of the most interesting papers in American pale- 

 ontology—Chamberlain's and Barrell's— concern the fresh- 

 water origin of the vertebrates. Until 1900 it had been 

 accepted that the seat of vertebrate evolution had been 



