The Crinoids from 13r. S. Bock's Mxpeditiox to .Iai-an KM 4. 17!) 



I have therefore preserved the two species as different types 

 of species value. 



The newly proposed form oniatus 1 might possibly have been 

 able to consider as a variety, if I had had more plentiful material at my 

 disposal. It differs from the chief species by the well developed orna- 

 mentation of the internodal joints and. probably, by a somewhat greater 

 number of arms (Sp. 22 with about LX arms). Ne\erthcless it might 

 be considered that the greater number of ai-ms is a mere chance: cf. 

 the 20"' specimen (observe also that Sp. 20 — 22 are rather large spe- 

 cimens). Therefore, keeping in view the appearance of the stems in 

 M. rotundiis, 1 will not set u]) a new \ariet.y based only onthe orna- 

 tion of the internodals and becaus(! of that I lune |)refei-red only 

 to note the new type as a »form». 



1 do not consider that the change in the lunnber of internodals 

 in the abo\"e-described specimens causes any sub-di\iding into \-arie- 

 ties. (Sp. 8, 9 and 20 show specially high figures). It is to be noticed 

 that the very youngest specimens have a smaller number of inter- 

 nodal joints. That is because the middlemost internodal joints have 

 got a complete cirrus-whorl. There arc often on the other internodals 

 too small prominences where the cirrus ought to have been inserted 

 if the joint had been a nodal. 1 do not doubt that the still unknown, 

 very small young forms of this family will turn out to have all or 

 most internodal joints pi-ovided with cirrus-like prominences, thus 

 appoaching the type that is shown in the distal part of the stems of 

 Rhizocriniis. The differentiation into nodal and internodal joints is 

 certainly a secondary phenomenon. — 



