REPORT ON THE CRINOTDEA. 77 



difference of position occurs in the short cirri of Antedon carinata, numbers of which 

 were found by the Challenger at Bahia ; while many instances of the same kind occur 

 among the Comatulse dredged by the Challenger in the Eastern Archipelago and by the 

 " Blake" in the Caribbean Sea. (See also PL XXXIII. fig. 6, and PI. LXX.) 



I do not think therefore that Perrier is entitled to consider Eudiocrinus atlanticus as 

 a specially interesting modification of the Comatula-type with regard to its locomotive 

 powers, for it presents no peculiarities which do not occur in several species of Antedon. 

 It is true that like other species of the genus (PL VI. fig. 1 ; PL VII.) it has large and 

 powerful muscular bundles between the successive arm-joints ; and from this perhaps we 

 may draw the conclusion that it was " un habile nageur." But the last sentence of the 

 passage quoted above, wherein Eudiocrinus atlanticus is contrasted with Antedon and 

 Actinometra as regards its swimming powers and mode of life, entirely ignores all that 

 has been written upon the subject of late years. 



It is true that the muscular bundles of Eudiocrinus, as also those of Atelecrinus 

 (PL VI. figs. 4, 7) and of many deep-sea Coinatulas, appear large by contrast with those 

 of other types in which they do not appear prominently on the ventral surface of the 

 arms, owing to their being covered by a thick and more or less opaque perisome. But 

 when this is removed the large muscular bundles become visible, as seen in Dr. Carpenter's 

 figure of Antedon rosacea. 1 The same is the case in Antedon eschrichti, the muscular 

 bundles of which, when properly exposed, have at least as great a relative size as those of 

 any Eudiocrinus ; and if the size of the muscle-plates on the arm-joints be any criterion 

 of the strength of the muscular bundles attached to them, there is little to choose in this 

 respect between Antedon eschrichti, Actinometra paucicirra, and Actinometra nobilis. 



The position assumed by the cirri, and the appearance of the muscular bundles on the 

 ventral surface of the arms of Eudiocrinus atlanticus, are not therefore characters of such 

 importance as Perrier seems to think, when he contrasts this type with " la plupart des 

 Antedon." I do not see that this species, with its cirri between 15 and 20 mm. in length, 

 is any less well adapted for fixing itself to submarine bodies, than Antedon phalangium 

 and many other species of the same genus which have cirri like those of Eudiocrinus 

 atlanticus (PL XXVIII. ; PL XXX. figs. 4. 8 ; PL XXXIII. fig. 6). Neither do I know 

 what authority Perrier has for his statement that most species of this genus swim but little, 

 while implying that Eudiocrinus atlanticus swims a good deal. It certainly cannot be 

 anything more than a somewhat hasty generalisation, which he could not possibly have 

 made had he stopped to consider why the muscular bundles of Eudiocrinus appear so 

 large in contrast to those of " la plupart des Antedon." But when he goes on to speak 

 of the species of Actinometra as being those which are specially adapted to fix themselves 

 and to swim but little, he falls into very considerable error. For, as will be shown 

 immediately in reference to another part of his description of Eudiocrinus, he has not 



1 Phil. Trans., 1866, pi. xxxiv. fig. 2. 



