22 



JAMES A. GRIEG 



[REP. OF THE "MICHAEL SARS" NORTH 



Stations 



14 



25 B 



25 B 



24 



25 B 



24 



41 



41 



41 



41 



41 



95 



Diameter 



26 



42 



49 



56 



59 



62 



65 



70 



81 



83 



90.5 



130 



Arm-radius 



13.5 



22.5 



26 



30 



31.5 



32 



35 



37 



43 



44 



48.5 



69.5 



Disc-radius 



9 



13 



14 



18 



16 



21 



21 



21 



26 



23 



30.5 



47 



Size of the mad- 



























reporic plate .... 



05X1 



0.7 X 1 



0.7 X 1 



0.7 X 1-2 



1 X 1-2 



1 X 1-5 



0.7 X 1-2 



1.2 X 1-7 



1.5X2 



1.7X2 



1.5X2 



2X3 



Distance of the 



























madreporic plate 



























from centre of 



























disc 



3 



4.5 



5 



5.5 



6 



7 



7 



7 



8 



8 



9 



13 



Number of dorso- 



























marginal plates.. 



6 





9 



6-7 



10 



7-8 



9—10 



8 



8—9 



12 



7—8 



9—10 



Number of ven- 



























tro-marginal pla- 



























tes 



7 



8 



9—10 



7 



10 



8 



9—10 



9 



9 



14-15 



9 



10-11 



r:R 



1 : 1.5 



1 : 1.73 



1 : 1.86 



1 : 1.67 



1 : 1.96 



1 : 1.52 



1 : 1.67 



1 : 1.76 



1 : 1.6G 



1 : 1.91 



1 : 1.59 



1 : 1.48 



The largest of Perrier's specimens had an arm-radius 

 of 67 mm., and a disc-radius of 38 mm 1 ) It was thus 

 but a little smaller than that from stat. 95, from which 

 it differs by proportionately longer arms, the proportion 

 r:R was 1 : 1.76, while in the specimen from stat. 95 it 

 was 1 : 1.48. The latter has not, however, attained the 

 maximum growth of this species. Farran mentions in 

 „The deep-waters Asteroidea, Ophiuroidea and Echinoidea 

 of the West Coast of Ireland 2 )" two specimens of consider- 

 ably larger size, which measured respectively: R 86 mm 

 and 95 mm, r 50 mm and 63 mm, r:R = 1 : 1.72 and 

 1 : 1.51. 



The specimen from stat. 95 is remarkable for its 

 short arms. Apart from a few exceptions the "Michael 

 Sars" specimens had longer arms and in a few of them 

 the arm-radius was even nearly twice as large as the 

 disc-radius. According to the measurements quoted by 

 Perrier the proportion r : R seems to vary between 1 : 1.62 

 and 1 : 1.78. The largest specimens had the largest arms, 

 while in the "Michael Sars" specimens in which r : R 

 varied between 1:1.48 and 1:1.96, the middle-sized 

 individuals had proportionately the longest arms. Indivi- 

 dual variation is, however, present; thus the 62 mm. 

 specimen from stat. 24 was very short-armed (1 : 1.52); 

 while the 59 mm. specimen from stat. 25 B had very 

 long arms (1 : 1.96). The Prince of Monaco's largest 

 specimen had an arm-radius of 42 mm. and a disc-radius 

 of 24 mm, r : R = 1 : 1.75 3 ). 



J ). Ed, Perrier: Echinodermes, Exp. Sci. du "Travailleur" et du 

 'Talisman", 1894, p. 391, tab. 25, figs. 1 a - b. 



2 ) . Fisheries Ireland, Sci. Invest. 1912, no. 6, (1913) p. 10. 



3 ) . Koehler: Echinodermes, Res. Camp. Sci. Monaco, Fasc. 34, 

 1909, p. 85, tab. 2, fig. 7. 



The arms were distinctly marked off in most of the 

 specimens, the terminal plates being separated from the 

 abactinal plates by 3 or 4 dorso-marginal ones or even 

 by 5 plates in the most long-armed specimen. 



The abactinal plates of the larger specimens were 

 angular and furnished with one row of large round 

 granules, but in other respects bare. In the smaller 

 specimens, on the other hand, the majority of the plates 

 were granulated throughout. The abactinal plates are 

 thus originally entirely covered with granules, but the 

 granulation disappears gradually with the growth of the 

 individual, except along the border of the plates. It first 

 disappears in the plates of the papularium, which in the 

 smallest specimen bore only a ring of granules along the 

 border, while the remaining abactinal plates were still 

 covered with them. 



The dorso-marginal plates of the large specimen from 

 stat. 95 bore one row of granules along the border, but 

 were otherwise bare. The ventro-marginal plates were 

 granulated along the border nearest the dorso marginal 

 plates, and the same was the case with a larger or smaller 

 portion of the ventral part adjacent to the actinal plates. 

 The ventro-marginal plates of the smallest specimens were 

 covered with granuls throughout, and the lateral portion 

 of the dorso-marginal plates was likewise granulated, while 

 the dorsal portion w'as bare. In the remaining specimens 

 the granulation of the dorso-marginal plates was similar 

 to that of the largest specimen, while the ventro-marginal 

 plates presented transition forms between the granulation 

 of the largest and that of the smallest specimen. The 

 terminal plates were bare. 



The papularium was very large and papulae were 

 wanting only in a comparatively small interradial area 

 from the centre of the disc to the middle interradial dorso- 



i 



