REPORT ON THE CRINOIDEA. 227 



The pinnules of the fourth and fifth brachials are sometimes twice its length, reaching 

 12 mm., and consisting of about eighteen elongated joints, with spines at their distal 

 ends. The next pinnule is not half the size of this pair, and is smaller than that on the 

 second brachial, while the next pair are the smallest on the arm. after which the length 

 of the pinnules increases slowly. 



Disk very much incised, and quite naked ; sacculi very abundant on the arms and 

 pinnules. 



Colour in spirit, — the skeleton reddish-brown, and the perisome rather darker. 



Disk 8 mm.; spread 12 cm. 



Locality.— Station 192, September 26, 1874 ; near the Ki Islands ; lat, 5° 49' 15" S., 

 long. 132° 14' 15" E.; 140 fathoms; blue mud. One specimen. 



Remarks. — This is a very singular species, the general relations of which are with 

 Antedon marginata and Antedon sequipinna; but it is distinguished from them both, 

 and from all the other bidistichate forms of Antedon, by the peculiar distribution of the 

 pinnules. The arrangement of the arm-divisions seems to be like that of Pentacrinus 

 maclearanus, palmar axillaries being only developed on the two outermost of the four 

 secondary arms on each ray, so that the grouping of the arms is 2,1,1,2. In one ray, 

 however, a palmar axillary is missing, so that the total number of arms is twenty-nine, 

 and not thirty as it would otherwise be. 



There is never any pinnule on the third brachial, as is also the case in Antedon 

 disciformis (PI. XXXIX. fig. 4) and in the ten-armed Antedon informis of the 

 Milberti-groi\]) (PI. XXXIII. fig. 3) ; and that of the second brachial is also absent in 

 some arms. It is undeveloped on the inner arm of every pair which springs from a 

 palmar axillary, and it is occasionally also absent on the two inner arms of the ray which 

 are borne directly on the distichal axUlaries ; though it is sometimes present, as in the 

 two central arms of the lowest ray represented in PI. XLIV. fig. 2, while it is always to be 

 found on the two outer arms of the ray. Of the two single arms which are borne on the 

 inner faces of the two distichal axillaries, one may have a pinnule on the second brachial 

 and the other not ; and there appears to be no constancy as to its occurrence in this 

 position. When present, it is somewhat smaller than its fellow on the outside of the ray. 

 The large pinnules of the fourth and fifth brachials are tolerably equal on all the arms, 

 that on the fourth being perhaps a little the longer ; but the pinnule of the sixth brachial 

 is much smaller again, and the next pah- still more so, barely reaching 4 mm. 



The disk has a large pentagonal perisome (PI. XLIV. fig. 2), but is much incised, 

 and the anal tube appears to be quite at its margin, so far as one can judge from the 

 mutilated condition of the specimen. The sacculi do not appear to occur on the disk, 

 but they are well developed on the arms, and especially so on the pinnule-ambulacra. 



