The Crinoids from Dr. S. Bock's Expedition to Japan 1!H4. 11 



ing stem has given figures from 2 to 2,5 metres. It is, liowever, to 

 be noticed tliat large forms, such as M. rotundus, probably have stems 

 which during their increase of thickness become a good deal longer. 

 Concerning both the first-mentioned species and the latter ones it is 

 very possible that the length-increase of the stem is continued even 

 after the increase of thickness has ceased. A couple of measurements 

 have shown that the thickness of the stem can even decrease proxi- 

 mally, which ought probably to be regarded as a phenomenon of old age. 

 The study of the components of the division-series has led to interes- 

 ting results which will be treated in a special investigation in connection 

 with the question of the new formation and augmentation of the num- 

 ber of arms in the genus Metacrimis and in the discussion of the rela- 

 tion between pinnula? and arms. 



Concerning the terminology I have used the same names as 

 in my work upon the Mjöbergian Crinoids, i. e. about the same as 

 Bather, A. H. Clark etc. have employed. 



Thus R (the radial) is the first ossicle of the arm. The ossicles 

 between the i-adial und the first arm-ramification are denoted as primi- 

 brachials 1, 2. etc. (I Br 1, I Br 2). The last ossicle before this arm- 

 division is an axillary (I Brax), carrying on its distal surface two se- 

 condary arms. If the animal has only X ai-ms there are no further 

 arm-ramifications, otherwise after the I Brax the secundibrachials {II 

 Br:s) follow with the 2 nd, 4 th oi-, among the stalked crinoids, even a 

 more distal segment forming an axillary. On this a new division-series, 

 the tertibraehial (III Br), may possibly arise, then perhaps a IV Br 

 series and so on. The segments of the arm-branches that are not 

 further divided are signified as brachials (Br) with the number of the 

 segments counted from the last axillary. 



The number of the Cirri (C) as well as of the arms is written 

 in roman figures, the number of the segments in arabic ones. By the 

 word »whorl» in the description of cirri I mean their arrangement in 

 a horizontal line, but I speak of »row» when referring to their arrange- 

 ement in a vertical line. 



The pinnules (P) are denoted on the outside of the arm by 

 ordinals, on the inside they are indicated by letters (a, b. c). I Br (Cos- 

 tal), II Br (Distical), III Br (Pahnar), and IV Br (postpalmar) pinnules I 



