1894.] ECHINC-DERMS OF MACCLESFIELD EA>'K. 399 



Arras about 100 mm. long ; diameter of disc 10 mm. ; length 

 of cirri up to 28 mm. 



Macclesfield Bank, 31-36 fms. H.M.S. ' Penguin.' 



Antedon BASSETT-smTHi, sp. nov. (Plate XXIV.) 



This is one of the late Dr. H. Carpenter's spinifera -group, and 

 belongs to that section in which there are from fifteen to twenty- 

 five cirrus-joints. The cirri are not arranged in definite rows, and 

 the sides of the distichals are not flattened. 



Centrodorsal rather large, slightly hollowed in the centre, which 

 is bare of cirrus-pits ; the cirri in three planes at the side, about 

 forty in number, with from twenty to twenty-five joints, some of 

 which are considerably elongated ; in the distal half they have a 

 slightly projecting free edge, but there is no distinct spine. 



Arms, probably, more than forty in number, stout, widely 

 separated at their bases, where the disc-incisions are deep. First 

 radial obscured, the second wide, the third almost triangular; two 

 distichals, two palmars ; the latter may or may not be united 

 by syzygy. In the syzygies of the arms the most extraordinary 

 variations occur : sometimes the first two brachials are united by 

 syzygy, sometimes (to use the usual terminology) the third is a 

 syzygy, sometimes both first and second and third are. The first 

 arm-joints are squarish, the succeeding alternately wider and 

 narrower on either side. The second and third pinnules ordinarily 

 have the two basal joints much wider than the rest and of a 

 characteristic shape (Plate XXIV. figs. 5 & 6); none of the pinnules 

 are either stout or long. 



I must confess that I am quite at a loss to know how to explain 

 the extraordinary divergencies exhibited by the syzygies of this 

 species. It is, of course, a great pity that there is only a single 

 example of. it, and it would be rash to say that it destroys the 

 generalizations to which long study of a number of species and 

 specimens led Dr. H. Carpenter; but, on the other hand, it cannot 

 but shake our belief in the universality of the conclusions drawn 

 up by Carpenter on pp. 41-46 of the ' Challenger ' Report on the 

 ' Coinatulse.' If it be merely an abnormality it is a case in 

 which monstrosity is really carried too far, and is one that is, 

 probably, quite unequalled by any known Crinoid. So far as I 

 know, and, indeed, so far as I can, after diligent search, discover, 

 the only recorded case of striking irregularity in the position of 

 the syzygies is that of the G-ottingen specimen of Antedon mc- 

 cronema, of which Dr. C. Hartlaub remarks l : — " Bemerkenswerth 

 ist an ihm die unregelmassige Lage der ersten Syzygie, die zwischen 

 dem 3.4. und 6. Brachiale wechselt." But here we have not onlv 

 two conditions which have been supposed to be mutually exclusive 

 in different arms of one specimen, but these very two conditions 

 occur on one arm. Did we know something of the function of 

 the syzygies, it \vould be easier to come to a decision, but as our 

 knowledge of that function appears to be summed up in the state- 

 1 Nova Acta Acad. Caes. L.-C. lviii. no. 1, p. 78 (Halle, 1801). 



