The Ceinoids from Dr. S. Bock's Expedition to Japan 1914. S!) 



have tlie most arms, but rather tlie reverse. It is probable, as I have 

 suggested when treating the above-mentioned species, that the question 

 of catching the food plays a certain rôle, but possibly (though not very 

 hkely, cosidering that I have often seen »duplicative» regenerates 

 situated on Br 1, but never a single arm regenerated from tlie same 

 ossicle) one might also connect the phenomenon with the fact tiiat the 

 family Colobometridœ strongly tends to a X-ai-med type and that this 

 is reached only after a transition stage with moi-e than X arms. 



By the small transverse carination (on some segments replaced 

 by a pair of microscopic tubercles) on the proximal cirrals the new 

 species proves itself to be a form of an OHgophreai type, though other- 

 Avise it presents much that reminds us of certain Ferometrins (the rela- 

 tively large size of the centrodorsal cavity and the position of the 

 rosette, which only radially forms »spout-like» processes). 



The new species approaches most to C. manca, from which it 

 iiiffers by a smaller and less discoidal Cd, by longer cirrals, which 

 have only inconspicuous carinations, by the absence of III Br — s, 

 by the short interval between the syzygies, and by P2 being almost 

 smooth. 



The species is an interesting form, showing a strong tendency 

 of convergence towards the Macrophreat type. 



•68. m Cyllometra disciformis (St. .^5) 68) Arm-stump with a genital pinnule "/i, 69) Cirrus »/i; 70, 71 

 Trnpiometra encrinns [St. 45), 70) Cirrus Vi, 71) Distal pinnule °/i; 72, 73 Pectinometra flavopur- 

 pnrea 72) P, "/i, 73) Distal pinnule (4—5 pairs of Sacculi per segment) 'Vi; 74) Cenometra belln 

 Cirrus »/i : 75. 76 Neometra multicolor (St. 12). 75 a) Distal pinnule (the tip broken) "/i, b) The 



tip of the pinnule from another specimen (in Dr Mortensen's collection) 'Vi, 76) Pi '*/i; 77. 78 Crosso- 

 metra septcntrionnlis (St. 36), 77) Pu (the 7 last segments broken) '*i, 78) Distal pinnule '*/i; 79—83 

 Diodontometra Bocki (St. 56) 79 a) The penultimate segment Tiewed from the proximal end, b) The 

 same segment viewed from the distal end. X 17 V2, 80) P, "/1, 81) Cd with the cirri arranged in 

 radial groups (observe the distal face of I Br 1) ='/1. 82) Genital pinnule "1, 83) Distal pinnule '*,i. 



Nova Acta Reg. Soc. Sc. Ups.. Ser. 4. Vol. 5. N:o G. Impr. »/3 1922. 12 



