A MONOGRAPH OF THE EXISTING CKINOIDS 229 



In the specimen collected by l^r. Th. Mortensen at Thatch Island there are 20 

 arms 105 mm. long; all the IIBr scries are present, and all are 4 (3+4). The centro- 

 dorsal is 3 mm. across the flat dorsal pole. The cirri are XXX, 11-12, 11 mm. long. 

 The division series are narrow and well separated. 



Under the name of meridionalis-rubiginosa Hartlaub recorded 3 small 10-armed 

 specimens which very clearlj' show the dark arm stripe of rubiginosa. The first is 

 from Blake station 155, the second is from Florida, and was determined apparently 

 by P. H. Carpenter as rubiginosa, and the third is from Blake station 127. All 3 have 

 moderately broad division series, and the IBr, are in lateral contact. Ilartlaub says 

 that the specimen from Blake station 155 has the centrodorsal and cirri of meridionalis 

 [echinoptera], and in the proximal half of the arms short, not triangular, brachials with 

 everted ends; there are no spines on the pinnules. The specimen from Blake station 

 127 has a few somewhat elongated cirrus segments; it does not have the more or less 

 triangular basal pinnule segments in the proximal portion of the arms which are so 

 characteristic of meridionalis [echinoptera], so that,more than the other 2, it approaches 

 rubiginosa. But, on the other hand, it differs from rubiginosa in the absence of spines 

 on the pinnules. The specimen from Florida, in contrast to the other 2, has spiny 

 pinnules, and also in other ways is the most like rubiginosa of the 3. The cirri 

 unfortunately have been lost. 



Three specimens from Blake station 155, determined by Hartlaub as meridionalis- 

 rubiginosa, are very similar to the example from Florida just mentioned and, like it, 

 have spiny pinnules. They are accompanied by the name rubiginosa, the determina- 

 tion apparently having been made by Carpenter. Two of them show a dark arm 

 stripe. In their cirri, broad IBr series, flat centrodorsal, and rather short brachials 

 they show, according to Hartlaub, characters of meridionalis [echinoptera.] 



The specimen from Blake station 285 has 18 arms. 



In the specimens from Brazil recorded by Rathbim the cirri were XII-XVI, 

 11-12. The arms numbered from 11 to "at least 20," and were 45 mm. long. 



Carpenter remarked that this Atlantic species may readily be distingmshed by 

 the greater relative length and more quadrate shape of the brachials, the edges of 

 which are by no means so spiny as in Capillaster multiradiata and its alUes. The 

 relative shortness of the intersyzygial interval and the frequent plating of the inter- 

 radial perisome he considered as distinctive characters of minor value. 



He noted that in tliis species the position of the mouth seems to be somewhat 

 variable. So far as he was able to make out, it is radial in the Caribbean specimens, 

 but interradial in the Brazilian. 



Neither of the Caribbean specimens which he was able to examine had any 

 IIIBr series, and these were sometimes absent in those from Brazil. 



Abnormal specimen. — The example from Bahia figured by Carpenter (pi. 60, 

 fig. 3) has 8 of the IIBr series 4 (3 + 4) and 2 of two ossicles only, though this is not 

 mentioned by Carpenter in the text. 



Localities. — Bibb station 162P (Nos. 2 and 3); off Orange Key, Bahamas; 16 

 meters; April 1, 1869 [Pourtal^s, 1869; Hartlaub, 1912] (1, M. C. Z., 496). 



University of Iowa's Bahamas expedition; no locality [H. L. Clark, 1917]. 



