A MONOGRAPH OF THE EXISTING CRINOIDS 23 



when present, are 4(3+4). The division series are narrow and very widely separated 

 laterally. They are high and strongly convex dorsally, and small, abrupt, and rather 

 high synarthrial tubercles are present at the synartliries. The ventrolateral borders 

 of the ossicles bear rounded tubercular lateral processes at the ventrolateral angles 

 that on the division series as a whole appear as a row of high rounded widely separated 

 teeth. The outer division series and arms are unusually narrow. 



The arms in the type specimen are 15 + 15+14+21 + 15=80 in number, 120 mm. 

 long. The first brachials are trapezoidal, nearly twice as broad as the median length 

 and nearly twice as long exteriorly as interiorly, inwardly united for the proximal 

 half, the distal halves diverging at approximately a right angle. The second brachials 

 are trapezoidal, and are somewhat larger than the first. The first syzygial pair 

 (composed of brachials 3 + 4) is about half again as long as broad, and is somewhat 

 constricted centrally. The next five brachials are approximately oblong, nearly as 

 long as broad, after which the brachials become triangular, about as long as broad. 

 The proximal oblong brachials are narrowly and faintly carinate. 



Syzygies occur between brachials 3 + 4, 9+10, and 13 + 14, and distaUy at inter- 

 vals of 3 or 4 muscular articulations. The second syzygy is sometimes between 

 brachials 8 + 9 or 10+11, and is sometimes absent. The first syzygial pair is occa- 

 sionally followed immediate^ by a second, consisting of brachials 5 + 6. 



Pp is 13 mm. long and is composed of 18 segements (in three cases) of which the 

 first is slightly broader than long, the second and thhd are slightly longer than broad 

 (the third usually longer than the second), and the fifth and following are from two and 

 one-half to three times as long as broad. The sLxth and following segments have 

 the distal end on the side toward the arm tip abruptly everted and finely spinous. 

 The pinnule is rather stiff, though not rigid. 



Pi is 24 mm. long, very stiff and rigid, and much stouter than P„ with 18 seg- 

 ments of which the first two are about one-third again as broad as long, the third is 

 about one-third again as long as broad, and the remainder are between two and one- 

 half and three times as long as broad. From the fifth onward the distal edges of the 

 segments on the side toward the arm tips are abruptly and conspicuously everted and 

 coarsely spinous, this character increasing in extent distally. 



Pa is 23 mm. long with 17 segments, similar to Pi but more slender with the 

 segments about three times as long as broad. 



Pa is 23 nmi. long with 17-18 segments, and resembles P2. 



P4 is 15 mm. long with 14 segments, shorter and more slender than P3, though 

 otherwise similar to it. 



P5 is 7-8 mm. long with 13-15 segments, very slender, dehcate, and flexible. The 

 first segment is about twice as broad as long, the second is trapezoidal and about as 

 long as its proximal width, and the remainder are about three times as long as broad, 

 becoming longer distally. The pinnules following are shorter and weaker. 



The distal pinnules are 7 mm. long, very slender and dehcate, with about 15 seg- 

 ments of which the first is about as long as broad, the second is about one-third again 

 as long as broad, and the fourth and followmg are about four times as long as broad. 

 From the third onward the segments have finely spinous distal ends. 



Pa is always absent. On the inner arms on a IIBr series P„ P2, P», and Pb are 

 usually absent; rarely Pi is present and the others absent. 



