A MONOGRAPH OF THE EXISTING CRINOIDS 449 



The distal intersyzygial interval is 6(-17) muscular articulations. P, is 5.5 mm. 

 long with 11 segments. Pj is 6 mm. long with 11 segments. P3 is 5.5 mm. long with 

 12 segments. P5 is 7 mm. long with 10 segments. Pg is 7.5 mm. long with 13 seg- 

 ments. The distal pinnules are 11.5-12 mm. long with 19 segments wliich are from 

 two to two and one-half times as long as broad. 



Another specimen from station 53 has the cirri XVII, 65-72, 25-40 mm. long. 

 The radials are three times as broad as long with a dorsal crest. The 12 arms are 

 55 mm. long. The brachials develop dorsal spines from the fiftieth onward. The 

 distal intersyzygial interval is 4-6 muscular articulations. P, is 5.5 mm. long with 

 11-12 segments. P2 is 6 mm. long with 11 segments. P3 has 9 segments. The distal 

 pinnides are 8.5-9.5 mm. long with 17 segments which are twice as long as broad. 



In another specimen from station 53 the cirri are XVIII, 65-85, 36-53 mm. 

 long. The radials are three times as broad as long with a dorsal crest. The 10 arms 

 are 75 mm. long. The brachials develop a dorsal spine from the fiftieth onward. 

 The distal intersyzygial interval is 5-7 muscular articulations. P, is 5.5 mm. long 

 with 13 segments. P2 is 6 mm. long with 12 segments. P3 is 5-8 mm. long with 11 

 segments. P5 is 7 mm. long with 14 segments. The distal pinnules are 11-11.5 

 mm. long with 18-20 segments which are from two to two and one-half times as long 

 as broad. On one arm Pa has grown out to a complete new arm. 



Another specimen from station 53 has the centrodorsal rather low. The cirri 

 are typical, XIV, 55-64, 30-35 nmi. long. The radials are twice as broad as long 

 with a dorsal crest. The elements of the IBr series and first two brachials have a 

 very indistinct carination. The 11 arms are 70 mm. long. The brachials develop 

 dorsal spines, which are rather low but increase rapidly in size in the last 10 mm., 

 from the fiftieth brachial onward. The distal intersyzygial interval is 5-6 muscular 

 articulations. P, is 5 mm. long with 13 segments. Pj is 5.8 nmi. long with 11 seg- 

 ments. P3 is 5.8 mm. long with 9 segments. The distal pinnules are 11.5 mm. 

 long with 18 segments which are two and one-half times as long as broad. 



In another specimen from station 53 the cirri are XT, 60-65, 25-35 mm. long. 

 The centrodorsal is sharply conical, 2.5 mm. high. The radials are three times as 

 broad as long with a dorsal crest. The 11 arms are 50 mm. long, ivith 80-00 brachials. 

 The brachials develop dorsal spines from the fiftieth onward. The distal inter- 

 syzA'gial interval is 7-8 muscular articulations. The distal pinnules are 10 mm. long 

 with 18 segments which are twice as long as broad. 



Another specimen from station 53 has the cirri XVI, 50-60, 20-30 mm. long. 

 The 10 arms are 45 mm. long and are composed of 70-75 brachials which develop a 

 dorsal spine from about the fortieth. The distal intersyzygial interval is 5-7 muscular 

 articulations. Pj is 3.5 mm. long with 9 segments. P2 is 3.8 nmi. long with 10 seg- 

 ments. P3 is 3.5 mm. long with 9 segments. The distal pinnules are 9 mm. long 

 with 18 segments. 



A j'oung specimen from station 53 has the cirri XI, 20-21, 2.5-3 mm. long. 

 The first cirrus segment is short, the second is somewhat longer than broad, the third 

 is two and one-half times as long as broad, the fourth and fifth are twice as long as 

 broad, the sixth is half again as long as broad, distally broadened, and the seventh 

 and following are as long as broad with an inconspicuous dorsal carination which is 

 transformed distally into a dorsal spine. The opposing spine rises to a height equal 



