MONOGRAPH OF THE EXISTING CRINOIDS. 571 



Tlie actual total length of this specimen, from which the tips of the arms and 

 the distal portion of the column are missing, is 30 mm. ; the crown (with the arms) 

 as preserved measures 10 mm. Professor Sars estimates that in life the total 

 lengtli must have been a little over 40 mm. 



The column as preserved consists of ^2 segments, of which the two just below 

 the centrodorsal are discoidal or lamelliform. the third dish-like, and the follow- 

 ing, as usual, cylindrical and becoming progressively elongated, being in the middle 

 of the column from three to three and one-half times as long as broad, and swollen 

 at the two ends. The distalmost columnals become somewhat shorter. 



The centrodorsal, which, as in the adult, conceals the basals and the radials, 

 bears from 20 to 30 cirri (26 in actual count) which are without any definite order. 



The cirri midway between the base and the dorsal pole of the centrodorsal 

 are the longest and the most developed, being 5 mm. long and about 0.16 to 0.20 mm. 

 in breadth. Toward the pole the length diminishes to 1.5 mm., and the marginal 

 cirri are even less developed. 



The centrodorsal thus resembles that of the adult, in which the cirri are uni- 

 formly distributed over the surface, except on the small dorsal pole, and nimiber 

 between 30 and 40. 



The cirri are more or less curved, especially distally, the tip being u.sually 

 directed downward and slightly inward toward the column. The largest are 

 composed of 13 segments (the number in the adults varies from 13 to 19), which 

 are cylindrical and, excepting those immediately adjoining the centrodorsal, 

 slightly compressed laterally; they already show the elongate form characteristic 

 of those of the adults. The cirrals, especially in the proximal half of the cirri, 

 where they are somewhat more slender than in the distal half, are somewhat con- 

 stricted centrally; the distal end is a little broader than the proximal, and its 

 finely denticulate dorsal border overlaps slightly the proximal end of the segment 

 following, which gives a somewhat crenulate dorsal profile to the cirrus in lateral 

 view. As in the adult the last segment bears a strong immovable conical pointed 

 tei'minal claw, which is slightly recurved, at the base of which dorsally is the 

 shorter and less curved, often nearly straight, opposing spine. The smallest cirri, 

 situated about the dorsal pole, are composed of only 7 segments, but in all other 

 respects they agree perfectly with the larger just described. Near the rim of the 

 centrodorsal, one in each of the interradial angles of the calyx, are five cirri which 

 are almost as long and stout as the smallest of the ordinary cirri ; they are uni- 

 formly cylindrical and smooth throughout, without distinct articulation, but show- 

 ing very fine transverse annular rings, and their tips are obtusely conical ; in other 

 words, they resemble the five primary cirri at an early stage. Exactly comparable 

 cirri are seen also in the same place in the adults apparently throughout life, 

 always few in number and of different sizes, and always occurring between the 

 older cirri and the margin of the centrodorsal. 



The IBri has become much broader and therefore appears much shorter. The 

 IBrj (axillary) has become as broad as the IBr, and has attaijied its definitive, 

 almost rhomboidal, form. 



