The Crinoids from Dr. S. Bock's Expedition to Japan 191-1. 153 



nm nobilis with varieties and M. varians Döderlein lias (iistiiiguished 

 according to tlie below combined scheme: 



I Large species. Diameter of the stem ö — 7,5 mm. IV Brachials 

 ordinary. Internodals smooth, witliont distinct furrows between the joints. 



M. nobilis 



1) 8 internodal joints, ('irri extending over \ interiiodes. 

 Diameter of the stem 5 — 6 mm. 5 »Kadials» M. nob. var. smnatranus 



2) 9 — 10 internodal joints. Cirri extending over 3—4 internodes. 

 Diameter of the stem 6— 7,. i mm. 6(— 7) »Radiais» M. nob. var. Urnor iensis 



3) 10 — 12 internodal joints. Cirri extending over 3 internodes. 

 Diameter of the stem — 7 mm. 5 »Radiais» M. nob. var. nobilis. 



■I) 13 — 15 Internodal joints, otherwise as in the preceding va- 

 riety. Here is to be mentioned also the sp. from Siboga Stat 251, 

 253, 254. M. nob. var. murrayi. 



II Small species. Diametei- of the stem 4 — 5 mm. Rarely IV 

 Br-s. Internodal joints 6 — 8. Distinct furrows between the internodals. 

 Cirri extending over 4—5 internodes. M. varians. 



To which species ought the above-described specimens then to 

 be referred? From the point of view of the diameter of the stem and 

 the number of pinnulars they are most closely related to M. varians, but 

 by the number of internodals, L of cirri and number of cirrals, by the 

 occurrence of IV Br-s, by the number of internodes with interarticular 

 pores they approach M. nobilis and especially the varieties nobilis and 

 murrayi of this species. Why have I not referred them to these two 

 varieties, which moreover may scarcely be considered as more than 

 types of individual variation? The smallei' diameter of the stem in 

 my specimens is an important distinguishing mark, but merely because 

 of this I would not establish a new variety, as the difference might 

 be due to a difference in age. As I have pointed out above, the number 

 of the cirrals is to a certain degree in proportion to the size of the 

 animal. When therefore, in spite of the delicate stem, the Bockian 

 specimens have a number of cirrals i;eaching or exceeding that stated 

 for M. nobilis.^ the different diameters of the stems cannot be consi- 

 dered as due to differences of age. Besides, the proximal pinnules in 

 the new variety are shorter than both in M. nobilis and varians. 



Two of the previously described varieties of M. nobilis show in 

 separate characteristics an approach to M. varians: M. n. var. suma- 



Nova Acta Reg. Soc. Se. Ups., Ser. 4, Vol. 5. N:o G. Impr. ■'4 1922. 20 



