A MONOGRAPH OF THE EXISTING CRINOIDS 531 



brachials. The first brachials are shorter than the second, which is a little longer 

 exteriorly than interiorly. The first syzygial pair (composed of brachials 3+4) is 

 larger and almost squarish. From the ninth brachial onward there are some almost 

 triangular brachials, which very soon pass over into short more cylindrical brachials. 

 These last toward the ends of the arms become more squarish and finally longer than 

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

 15 + 16, and the distal intersyzygial interval is mostly 8 to 11 muscular articulations. 

 Arms arising from IBr axillaries have the second syzygy between brachials 9 + 10, 

 and those succeeding at intervals of at first 4 but later 7-9 muscular articulations. 



P! is about 8 mm. long and is somewhat slenderer and shorter than P 2 , which is 

 about 10 mm. long and is composed of 15-20 smooth segments, of which the majority 

 are elongated. P 3 is of the same size as PI. Then follows the shortest pinnule, after 

 which the length of the pinnules again increases, reaching about 13 mm. The maxi- 

 mum length of the distal pinnules is greater than the length of the pinnules of the 

 second pair (P 2 and P b ). In arms arising from a IIBr or IIIBr axillary the relative 

 sizes of the lower pinnules is somewhat less than those given, which are taken from 

 arms arising from a IBr axillary, and the difference in size between PI and P 2 is less 

 pronounced. The lower pinnules on the outer side of the arms, especially P 2 , are 

 longer than the corresponding pinnules on the inner side. The relatively slender 

 structure of the lower pinnules is characteristic. The disk is lacking. Sacculi are 

 thickly set on the pinnules. The color is dirty white, with about seven broad bands 

 of light brown on the arms. 



Hartlaub said that his, as it appeared to him undoubtedly new, species, has a 

 certain similarity to Heterometra savignyi in the form of the centrodorsal and in the 

 lateral freedom and the irregular division of the postradial series. In addition to 

 these features, the entire absence of synarthrial tubercles is noteworthy, and also the 

 entirely smooth surface of the arms and the relatively small size of the lower pinnules. 

 The distal pinnules, on the other hand, are long and give the arm a featherlike appear- 

 ance. Unfortunately only three cirri are preserved, and none of these appear to be 

 fully developed. 



In the specimens from Misharif Island, according to Chadwick, the central 

 portion, as far as and including the proximal brachials, is hi alcohol dirty white, and 

 the arms are alternately and broadly banded with the same color and dark brownish 

 gray. The dorsal and ventral faces of the cirri show the same contrast of color. 



In the four specimens from Suakim Harbor, especially the larger ones, the dorsal 

 surface of the centrodorsal is concave. There are 21, 21, 26, and 33 arms. In several 

 of the specimens syzygies occur between brachials 9 + 10 and 14 + 15, and in several of 

 the arms of the larger specimens the second syzygy is between brachials 22 + 23. 



The specimen from Ras-el-Millan has 24 arms 90 mm. long and resembles the 

 one from Um-el-Jerman. As is always the case in this species, the IIIBr series are 

 externally developed. 



Hartlaub said that the specimen from Jiddah and another from the Red Sea in 

 the Berlin Museum (No. 2019) differ from the specimens from the Red Sea collected 

 by Hemprich and Ehrenberg in being of much coarser structure, having especially a 

 much thicker centrodorsal. The specimen from Jiddah is besides noteworthy for 

 the considerable length of the pinnules of the second pan- (P 2 and P b ). In this it 



