A MONOGRAPH OF THE EXISTING CRINOIDS 



421 



In the specimen from near Koepang P 2 , P 3 , and P 4 are stiffened and enlarged. 

 The cirri have 19-21 segments. 



The specimen from Obi latoe has 27 arms 90 mm. long. P 2 is 13 mm. long, with 

 11 segments. P 3 is 10 mm. long, with 9 segments. P 4 is similar to P 3 , 7 mm. long, with 

 8 segments. 



The example from Lembeh Strait, Celebes, is small and is in process of adolescent 

 autotomy; it has 20 arms. 



The specimen collected by the Willebrord Snellius at Amboina has 30 arms 120 

 mm. long. The six arms on each postradial series are arranged in 2, 1, 1, 2 order. The 

 cirri are 30-33 mm. long, with 25 or 26 segments. P[ is 23 mm. long, with 39 segments, 

 very flexible, tapering more rapidly in the proximal fourth than beyond. P 2 is 30 

 mm. long, with 23 segments. P 3 is 22 mm. long, with 18 segments. P 4 is 18 mm. 

 long, with 19 segments. P 6 resembles P 4 and is 12 mm. long, with 15 segments. 



The 10 specimens collected by Dr. J. Brock at Amboina were thus described by 

 Hartlaub: The centrodorsal is thick, with convex sides and sometimes with a markedly 

 pentagonal lower border. The free dorsal pole is usually rather small and is marked 

 with small pits. The cirri are arranged hi two and a partial third irregular marginal 

 rows. The cirri are XXX-XXXV, about 25, from 18 to 28 mm. long, rather slender 

 and laterally compressed. The fifth-eleventh segments are elongated, and often have 

 thickened ends. In the proximal half of the cirri the ventral side of the distal ends of 

 the segments tends to overlap the proximal end of the segments following. There 

 are no dorsal tubercles or spines with the exception of the opposing spine. The radials 

 are entirely concealed. The IBr : are as long as the free sides of the shortly pentagonal 

 IBr 2 (axillaries) and are entirely free laterally. The IIBr and IIIBr series are 2. 

 The IIIBr series occur only on the outer sides of the postradial series so that as a rule 

 each of the latter bears 6 arms. Slight synarthrial tubercles are present. The elements 

 of the division series have slight thickenings on their lateral edges. The two ossicles 

 immediately following each axillary are partially united interiorly. The arms are 

 usually 30 in number and are 100 to 140 mm. long. The brachials are short. The first 

 seven or eight are thick discoidal, the 30 or so following are triangular with slightly 

 overlapping distal ends, and those succeeding are short wedge-shaped, later becoming 

 short discoidal, toward the ends of the arms about as long as broad, and finally some- 

 what elongated. Syzygies occur between brachials 3+4, again usually from between 

 brachials 13 + 14 to between brachials 26+27 (often at about the twenty-fourth bra- 

 chial), and distally at intervals of usually 8-1 1 muscular articulations. On arms arising 

 directly from a IBr axillary the second syzygy is between brachials 9 + 10 and the 

 distal intersyzygial interval is four or five muscular articulations. 



The pinnules of the first pair are slender and flagellate, but those of the three or 

 four following pairs are much thicker, stiff, straight, more or less sharp at the tip, and 

 spinelike. PI is usually longer on the outer arms of each postradial series than on the 

 inner. It measures up to 15 mm. in length and is composed of 20-27 cylindrical seg- 

 ments which, with the exception of the basal, are longer than broad. P. is a good deal 

 shorter than Pj. P 2 and P 3 , the two following stiff and spiniform pinnules on the outer 

 side of the arms, are usually markedly longer, and may reach 20 mm. in length. Some- 

 times they are both of the same size, but their relative length varies, and P 2 may be 

 either longer or shorter than P 3 . Both pinnules are composed of 9-15 (usually about 





