1898] WACHSMUTH AND SPRINGER ON CRINOIDS 345 



have much in common, were derived from the monocyclic genera 

 here referred to the Eeteocrinidae, or at all events from simple forms 

 like to them ; and that the dicyclic Thysanocrinidae (or Dimero- 

 crinidae), with their allies the Ehodocrinidae, were the descendants 

 of the dicyclic Eeteocrinidae ? It does not seem at all necessary to 

 lump monocyclic and dicyclic genera together in one family simply 

 because their interbrachial plates are ill-defined. 



Expressed in few words, an opinion as to the classification 

 offered in this magnificent monograph might fairly say that from an 

 anatomical standpoint it is by far the best that has yet been proposed, 

 but that it serves as a key to structure rather than as an epitome of 

 genetic affinity. The authors say : " We have not attempted to 

 construct a genealogical tree for the Crinoids, or a branch of one for 

 the Camerata, because such representations are generally unsatisfac- 

 tory, and in this case the tree would have to be constructed too 

 much upon imagination. Besides, our task is a humbler one. We 

 have rather preferred to content ourselves in this respect with 

 giving the general facts which our investigations seem to pretty well 

 establish, and such interpretation of them as appears to us reason- 

 ably consistent therewith. Within these limits we have hoped that 

 our generalisations may help to form a stable foundation upon which 

 others may raise more ambitious structures." The absence of a 

 phylogenetic tree is no cause for grumbling ; but had the authors, 

 when constructing their classification, kept pliylogenetic principles 

 more in view, they would probably have laid a foundation that 

 would have needed less taking up and relaying by those who, in 

 future times, shall complete the structure. Perhaps in the near 

 future I may be allowed to indicate the plan that such a foundation 

 might well follow. 



There has been no attempt here to review the work as a whole, 

 but while fault-finding may be postponed indefinitely, one can no 

 longer delay an expression of gratitude for the large amount of 

 information here collected and for the beautiful plates by Keyes, 

 Westergren, Ridgeway, Liljevall, and others, that illustrate the 

 work. Thanks also are due for the generosity of Mr Agassiz 

 in producing these costly volumes as part of the Memoirs of 

 the Museum of Comparative Zoology. But while expressing our 

 thanks and our appreciation, w^e are repeatedly saddened by the 

 thought that the senior author survived neither to receive the con- 

 gratulations so justly his due, nor even to see this offspring of his 

 maturity and full-garnered knowledge brought to the close that 

 would have crowned his life's work. F. A. Bathee. 



