A MONOGRAPH OF THE EXISTING CRINOIDS 199 



The IBr, are short, with the sides rounded off and laterally free. The pentagonal 

 IBr2 (axUlaries) are likewise short, and form with the IBr, a buttonlike synarthrial 

 tubercle. The 10 arms are about 40 mm. long. The first brachials are short dis- 

 coidal, as long interiorly as exteriorly, and are more or less united interiorly. The 

 second brachials are slightly larger than the first, and on the tubercular articulation 

 between them there is a little button. Both the first and the second brachials are 

 markedly broader than those succeeding. The first syzygial pair (composed of brachials 

 3+4) is not longer than the second bracial. Then follows a series of shorter dis- 

 coidal brachials which at about the eleventh pass over into short triangular brachials 

 of which the everted distal ends overlap the bases of those following. Each of the 

 discoidal brachials following the first syzygial pair has on the distal edge in the mid- 

 dorsal line a whitish buttonlike elevation which from the first syzygial pair or the fifth 

 brachial onward is very prominent. The distal brachials remain short, and toward 

 the arm tip become more cylindrical. Syzygies occur between brachials 3 + 4, 9+10, 

 18+19, 23 + 24, and 30+31; or between brachials 3+4 and 15+16; or between 

 brachials 8 + 9, 13 + 14, 17 + 18, 21+22, and 26+27; or between brachials 8+9, 

 16 + 17, 23+24, and 30+31. The syzygies are very variable in their position. On 

 one arm there is a syzygy between brachials 5 + 6 as well as between brachials 3+4. 

 Pi is apparently moderately short and stout with about 12-15 segments; but none 

 of the P, are preserved entire. The lower segments of this and the three following 

 piimules, with the exception of the basal, are carinate. P2 is obviously of about the 

 same size. It is composed of 16 segments of which the distal are elongated. At 

 the base Pi and P2 are equally stout. The stoutness decreases very rapidh' distaUy. 

 On the following three markedl}' weaker pinnules there are traces of carination on 

 the basal segments. The state of preservation is very poor. Apparently P3 or Pc 

 are the shortest pinnules. P4 is already longer again. All the pinnules are some- 

 what weak with the exception of the somewhat stiff first. P^ is somewhat weaker 

 than Pi, but is in no case preserved entire. None of the proximal pinnules are remark- 

 able for any special elongation, and none of them are flagellate. The color in alcohol 

 is dark brown with the centrodorsal and cirri very much lighter, the last almost white. 

 The pinnules and the buttonlikc tubercles on the earlier brachials are light brown. 

 Also on the dorsal surface of the brachials there is a larger light brown elevation. 

 The perisome is dark brown. 



The specimen from Obi latoe may be described as follows: The centrodorsal is 

 discoidal with the dorsal pole concave, 2 nmi. in diameter, and the sides slightly 

 convergent. The cirrus sockets are arranged in a single closely crowded marginal 

 row. The cirrus sockets are oblong with rounded angles, and are twice as high as 

 broad or even higher. The cirri are XV, 23-24, 15 mm. long. The first segment is 

 very short, and those following slowly increase in length so that the last 8 to 10 are 

 about as long as broad. The third and following segments have a finely serrate 

 transverse ridge which on the fifth-ninth is evenly bowed proximally, then becomes 

 straighter, and on about the twelfth becomes median, straight, with the crest convex 

 in end view. Farther out it becomes gradually narrower and lower, and on the ante- 

 penultimate segment is represented by a short transverse ridge situated proximal to 

 the middle of the segment. The opposing spine is small, slender, sharp, median, 

 and erect, rising to a height equal to less than half the width of the penultimate 



