BRYOZOA. 325 



the easy identification of species. In this respect the system is 

 not surpassed by any other, but being very largely an artificial 

 arrangement, it too often gives the student no clue to the nat- 

 ural relations of his species, which after all must be the first 

 aim of classification. For this reason, therefore, however well 

 adapted to the wants of the collector, the system can hold only 

 a provisional place. In his last worksf Mr. Busk has modified 

 his system to a considerable extent, so that it now seems much 

 more in accordance with nature than formerly. Still, while I 

 am not ready to admit that zooecial characters alone, should 

 be consulted in the framing of a system of classification, I am, 

 nevertheless, convinced that even now Mr. Busk credits zoarial 

 variations with more importance than they deserve. Palaeozoic 

 Bryozoa have received very little attention from this eminent 

 authority, and beyond placing some of the well known genera 

 into his suborder CYCLOSTOMATA, he does not account for them. 

 Hincks. whose work applies almost exclusively to recent re- 

 presentatives of the class, foEows and greatly enlarges the 

 system first proposed by the Swedish naturalist, Prof. F. A. 

 Sinitt. The latter aims at a genealogical classification, start- 

 ing with the supposition that the variations of species follow 

 the line of their development, and may be in a great measure 

 explained by it. In accordance with this theory he would ar- 

 range the Bryozoa in series according to the law of their evo- 

 lution. This doubtlessly opens a most interesting and im- 

 portant field for inquiry, one that I believe deserves more at- 

 tention than it has yet received. Still in the present stage of 

 our knowledge, the morphology of the class will be better ad- 

 vanced by recognizing and clearly discriminating between the 

 more constant variations than by uniting them upon grounds, 

 which only in rare instances can be unquestionable, into com- 

 prehensive specific groups under a single name. If a genealog- 

 ical arrangement in detail is ever possible, it will only be after 

 we have taken into account every departure from the simple 

 and more permanent types. Hincks himself thinks that Smitt's 

 arrangement of the Bryozoa in genealogical groups is prema- 

 ture, and his reduction of species excessive, as well as often 

 confusing, because unwarranted. 



t Challenger Reports. 



