Hauibach — Revision of the Blastoideae. 21 



into the interior of the calyx and varying in number according 

 to species from six to twelve or even more. These lamellae 

 are completely surrounded by a ribbon-like membrane ; see 

 Plate II. , Fig. 11. The water is admitted to the surface of the 

 membrane by longitudinal slits in the calcareous substance of 

 the roof between the vertical lamellae. Whether these slits 

 were covered or not I am unable to say on account of the 

 insufficiency of material for study. 



EARLIER CLASSIFICATION. 



As already remarked, the present classification is largely 

 based on external resemblances and is a very arbitrary one, 

 lacking a good foundation of morphologic as well as onto- 

 genetic characters, in consequence of which it becomes inade- 

 quate. This induces me to offer anew classification based on 

 determinative and permanent anatomical differences as well 

 as ontogenetic peculiarities. If the Blastoideae form an inde- 

 pendent class like the Crinoideae or Cystoideae, which I 

 believe is now generally admitted, then in revising the pres- 

 ent classification all names that have an ending ** crinus " 

 ought to be canceled and new and proper ones substituted for 

 them. This was already recommended by Quenstedt in 

 1876.* If this had been done it would have avoided the con- 

 fusion resulting from the retention of improper names and 

 from referring species to genera to which they do not belong, 

 especially when the author is doubtful about their propriety, 

 which is always indicated by a question mark, or from substi- 

 tuting new names for parts of the body which are not as 

 significant as the old ones. 



The ontogeny of extinct families can only be studied with 

 a large amount of material from one and the same locality, 

 which will enable us to make comparisons between the young 

 and adult specimens, to ascertain if all parts are keeping step 

 in the progress of development, or if one part has developed 

 more rapidly than the others, and in which direction this 

 development has taken place. 



For the purpose of proving the arbitrary condition I will 

 review the genus Granatocrinus and for the convenience of 



♦ F. A. Quenstedt. Petrefactenkunde Deutschlands, Vierter Band., p. 719. 



