A MONOGRAPH OF THE EXISTING CRINOIDS 



519 



The first syzygy is between brachials 3+4, the second is usually between brachials 

 16+17 (occasionally between brachials 17 + 18), and the distal intersyzygial interval 

 is 10-18 muscular articulations. 



The length of the lower pinnules varies. P 2 is composed of about 25 elongated 

 segments and is always longer than P^ Both of these pinnules on the outer arms 

 arising from each IIBr axillary are occasionally much longer than on the inner arms. 

 On the outer arms the length of PI may reach 12 mm., and that of P 2 may reach 18 

 mm. The basal segments of these slender pinnules are flat and somewhat enlarged, 

 and two of them are prominently or only slightly carinate. The three following 

 pinnules are small. P a and P b are markedly smaller than the corresponding pinnules 

 on the outer side of the arm (7i and P 2 ). The distal pinnules are 7 mm. long. 



The disk is 10 mm. in diameter and is deeply incised. Sacculi are closely placed 

 on the pinnules. 



The color in alcohol is light gray-brown. 



Color in life. Dr. H. L. Clark says that most of the specimens are gray or brown 

 of some shade and apparently unicolor, but a few of the lighter-colored ones seem to 

 have had a broad whitish band on the arms in life. 



Notes. The preceding description is adapted from Hartlaub's original descrip- 

 tion of Antedon tenera. 



The specimens from the Marshall Islands are variable. They are mostly refera- 

 ble to gyges, but some are fairly typical palmata, and some are intergrades. All have 

 30 arms, the six arms on each postraclial series arranged in 2, 1, 1, 2 order, except one, 

 which has 32 arms. 



One of the specimens from Port Denison in the Hamburg Museum has about 43 

 arms, which are about 85 mm. long. The cirri are XLII, 24-27, 17 mm. long. P 2 is 

 18 mm. long, very slender, with 33 segments. On the innermost arms of the IIBr 

 series (next the midradial line) P 2 is nearly as large as it is on the outermost arms of 

 each postradial series, but elsewhere it is small. On some of the arms P 3 resembles 

 P 2 . The proximal pinnules are less carinate than usual. 



A specimen from Bowen hi the Hamburg Museum is smaller than the one just 

 described. The two from Bowen in the Copenhagen Museum are typical and large. 



Bell said that in Antedon gyges, which he described from a single specimen from 

 Thursday Island, the centrodorsal is flattened, rounded, with the cirri arranged in 

 three rows. The cirri are rather more than XL, rather more than 30, and are 21 mm. 

 long. The fifth-tenth segments are longer than broad and those succeeding are 

 shorter, and provided, first of all, with a convex dorsal edge; this narrows into a wide 

 spinous protuberance, which becomes more and more spiny till the fairly well marked 

 penultimate (i. e., opposing) spine is reached. The radials are completely concealed, 

 and the IBr! are largely concealed. The IBr 2 (axillary) is triangular. There is a 

 slight median conical protuberance in the line of junction between the IB^ and IBr 2 . 

 The IIBr and IIIBr series are 2, and in both cases there is a slight conical protuber- 

 ance where the two ossicles meet, and in both cases also the more proximal of the two 

 ossicles is in close lateral contact with its fellow. The 41 arms are about 80 mm. long. 

 The first brachials are a little longer on their outer than on their inner side; along the 

 latter they are in close contact with their fellow. As the second brachial is also longer 

 without than within, there is a feebly marked diamond space interval. The first 



