A MONOGRAPH OF THE EXISTING CRINOIDS 423 



figure of the distal face of a IBfi seemed to show a median dorsoventral ridge, like 

 that which he figured in the corresponding part of Ileliometra glacialis. In reality, 

 however, there is not an articular ridge with a fossa on either side of it for the recep- 

 tion of a muscular or ligamentous bundle, but merely a division between the 2 sides 

 of the joint face which has a slight general convexity, and there is a corresponding 

 concavity, which is divided into 2 parts by a median line, on the proximal face of 

 the IBr axillary. 



If the 2 ossicles were really articulated, each face would have a median ridge and 

 lateral fossae instead of fitting into one another by a slight curvature. The median 

 line shown by Lov^n in his figure of the IBri also appears on an undoubted syzygial 

 face from further out on the ray, and Carpenter had no doubt whatever that the 

 union of the elements of the IBr series is really a syzj'gial one, although the usual 

 radiating ridges and furrows which are so characteristic of syzygies in coraatulids 

 are not present on the apposed faces. Traces of them are sometimes visible, however, 

 as a series of little elevations squarish or oblong in shape which radiate outward from 

 the central canal never, or only very rarely, reaching the margin, and produce the 

 appearance of a syzygial face with its ridges interrupted at intervals. But in other 

 cases the apposed faces are almost smooth. The syzygies further out on the rays, 

 however, are more normal in character. 



Carpenter noticed that the pinnules bear terminal combs as far as about the 

 twelfth brachial and that combs occasionally appear further out on the arms. 



He described the mouth as being usually subcentral and radial, with the primary 

 ambulacra arranged very much as in Antedon; but the anal interradius is considerably 

 the largest, with the anus near its margin and sometimes very difficult to find. The 

 interradial and interpalmar areas are often much plated. 



Abnormal specimens. — In this species it is not unusual to find the IIBr series 

 2 (1 + 2) instead of 4 (3 + 4). 



In one of the 2 specimens described by Hartlaub from Amboina both of the 

 IIBr series on one of the rays are 2(1 + 2). 



In the specimen from Jobie, 4 of the IIBr series are 2 (1 + 2). 



In the Challenger specimen from near Kandavu, Fiji, there are 4 IIBr 2 (1+2) 

 series, 2 on each of 2 IBr series. 



In the specimen from Fiji in the Copenhagen Museum 8 of the IIBr series are 

 2 (1 + 2), and only 2 are 4 (3 + 4). 



In the example from Fiji recorded by Carpenter as obtained from the Godeffroy 

 Museum (presumably the one in the Hamburg Museum), which was very likely one 

 of the same lot as the preceding, 4 of the IIBr series are 2 (1+2). 



In the specimen from Port Galera, Mindoro, with about 150 arms about 250 mm. 

 long, the IBri is missing on one ray. 



Localities. — New Harbour, near Singapore; shallows and muddy places; Capt. 

 Albert Vestoo [Lov^n, 1866; P. H. Carpenter, 1881 (as Singapore), 1888 (as Malacca)]. 



Cape Bantam, western Java [Kuhl and van Hasselt, 1869]. 



Siboga station 89; Pulu Kaniungan ketjil; 11 meters; coral; June 21, 1899 [A. H. 

 Clark, 1918] (1, Amsterdam Mus.). 



