472 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The radials are almost entirely concealed except for their angles which are 

 rounded, thickened, and turned upward so as to rise somewhat dorsally above the 

 level of the rest of the calyx. Their distal edges are incurved to receive the convex prox- 

 imal edges of the trapezoidal IBr b which are closely united laterally. The IBr 2 

 (axillaries) are short, barely half as long again as the IBr,, widely triangular, and in 

 contact laterally. The postradial series divide six times, all of the division series 

 beyond the IBr series being 4 (3 + 4). The division series are somewhat closely 

 united by plated perisome as far as the IIIBr axillaries, and the apposed sides of 

 contiguous ossicles are flattened laterally. The first segments after each axillary are 

 closely united laterally, and the second are but little separated. 



There are more than 80 arms which are probably about 125 mm. in length. The 

 first two brachials are broad and about equal in length, the second being the more 

 wedge-shaped. The next 2 or 3 brachials are roughly oblong and those following are 

 broad, wedge-shaped, with much raised and strongly overlapping distal edges. The 

 anterior arms are long and slowly tapering and are composed of 150+ brachials 

 which remain wedge-shaped until quite near the end, the later ones being relatively 

 shorter, blunter, and smoother, and the terminal squarer, elongating just at the end. 

 The posterior arms taper much more rapidly and end after about 120 brachials, those 

 of the distal third being bluntly wedge-shaped and the terminal squarer. 



The first syzygy is between brachials 3 + 4. The second is from between 

 brachials 10 + 11 to between brachials 14 + 15, usually between brachials 11 + 12 

 or 12 + 13. The distal intersyzygial interval is from 2 to 6, usually 4, muscular 

 articulations. 



The second elements of all the division series beyond the first have long and 

 fairly stout pinnules which decrease rather rapidly to that on the fourth brachial 

 (P 2 ) which is not, however, especially short or slender. The pinnules following are 

 considerably stouter and gradually increase in length but decrease in stoutness 

 after about the twenty-fifth brachial. The terminal pinnules are slender but not 

 unusually long, especially in the posterior arms. The large basal segments of the 

 stout lower pinnules slightly overlap one another, and the lowest pinnules have a 

 moderate terminal comb which disappears after about the eighth brachial. 



The disk is missing. There are several ungrooved arms. The width across the 

 radials is 14 mm. 



I examined this specimen at the Leyden Museum in 1910. It proved to be a 

 typical example of the form described in the Challenger report under the names 

 Actinometra duplex, Actinometra nobilis, and Actinometra regalis, and also mentioned 

 by Carpenter in 1884 as Actinometra dissimilis. The specimen appears to have had 

 IV cirri, of which the first 2 segments still remain. There are numerous more 

 or less obsolete cirrus sockets. Of the IIIBr series those on 2 rays have the typical 

 arrangement, 2 externally and 4 (3+4) internally. On a third ray 1 of the external 

 IIIBr series is 2, but the other 3 are 4 (3 + 4). On the remaining 2 rays all the IIIBr 

 series are 4 (3 + 4). The other division series are 4 (3 + 4) as usual. 



At the time of Carpenter's visit to Leyden he had not discovered the significance 

 of the curious variation in the IIIBr series, but simply considered division series of 

 2 replacing those of 4 (3 + 4) as abnormal. From his notes, therefore, he could not 

 see that his schlegelii was the same thing as the nobilis of the Challenger report. 



