192 THE VOYAGE OF H.M.S. CHALLENGER. 



of resemblance with the younger individuals of this type, as has been pointed out already. 

 The three specimens obtained were unfortunately all much mutilated, especially as 

 regards the cirri and pinnules ; but the peculiarities of the calyx are very characteristic 

 and serve to distinguish the type, though its precise relations to the other abyssal species 

 must remain somewhat uncertain in the absence of properly preserved individuals. 



A considerable portion of the first radials appears externally, and they are somewhat 

 wider than the second radials, while their angles are considerably produced both upwards 

 and inwards, so that the second radials are altogether prevented from coming into lateral 

 contact. This is especially well shown in the southern form (PI. XXXIII. fig. 2), but it 

 is not so apparent in the larger individuals from the North Pacific, except in an inter- 

 radial view of the calyx. Both this character and also the great length of the arm-joints, 

 the later ones of which are almost dice-box-shaped, indicate that the type is an embryonic 

 one, as is well seen on a comparison of figs. 1 and 2 on PI. XXXIII. with the larvae 

 represented in figs. 3 to 6 on PL XIV. The extension of the first radials upwards and 

 inwards, so as to keep the second radials from coming into lateral contact, is a larval 

 character which is better developed in the fossil Eugeniacrinus, and reaches its maximum 

 in the allied genus Phyllocrinus. 



A few poorly developed sacculi are present in the individual from 2600 fathoms 

 (Station 160), but I have not been able to find any indications of them in the two 

 specimens from the greater depth in the North Pacific (Station 244, 2900 fathoms). 



5. The Milberti-gvou-p. 



The first pair of pinnules comparatively small, and their component joints but little 

 longer than wide ; one or more of the second, third, and fourth pairs are longer and 

 more massive, with stouter joints than their successors. 



Remarks. — This is a somewhat heterogeneous group, and I have had considerable 

 trouble in working out an arrangement of it which I can regard as even approximately 

 satisfactory. The definition given above would almost include such forms as Antedon 

 angustipinna (PL XXIX. figs. 2-4) and Antedon tenuicirra (PL XXX. figs. 5-7), which 

 have been described in the JeneWa-group ; while Antedon parvicirra, which I have 

 placed in the Milberti-gxovi\), though with some doubt, has many points of resemblance 

 with Antedon rosacea and Antedon dtibeni. Indeed Antedon milberti itself exhibits 

 traces of the wall-sidedness of the radials and lower brachials which is so marked in the 

 Basicurva-grovi]). Then again, the ubiquitous Antedon carinata differs in many 

 respects from Antedon serripinna, Antedon milberti, and the typical members of the 

 group, so that another group may have to be established for it at some future time. 



The special character which distinguishes the Milberti-groi\]p is the large size of one 

 or more of the second, third, and fourth pairs of pinnules, which are borne respectively 



