484 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



agrees with that of the type specimen of aequipinna, and this is in every way very 

 similar to that specimen. 



The specimen from Siboga station 99 has 30 arms 60 mm. long. The lower pin- 

 nules are very slender. 



Of the three specimens from Siboga station 96 one has 30 arms about 60 mm. 

 long, one 27 arms about 60 mm. long, and the third about 30 arms about 65 mm. 

 long. In all three the enlarged lower pinnules, though long, are rather slender. The 

 last in color is deep purple, with the dorsal pole of the centrodorsal and the dorsal 

 side of the proximal half of the cirri white. 



The specimen collected by M. March in the Philippines is of medium size. 



Hartlaub said that in several specimens he had examined from Mortlock Island, 

 some in the Hamburg and others in the Gottingen Museum, the outer sides of the 

 postradial series are markedly flattened. The cirri are rather slender and short, 11 

 mm. long. P 2 is sometimes strongly recurved and sometimes quite straight and almost 

 spinelike. It is always slender and not especially thickened at the base, as described 

 by Carpenter in brevicuneata, and tapers to a very fine point. As in imparipinna P 2 

 is sometimes longer on the outermost arms of each postradial arms than on the inner 

 arms. In color these specimens are deep purple-violet banded with light gray-violet 

 on the arms. The alcohol in which they were preserved was stained deep red. 



Hartlaub said that these specimens are intermediate between Carpenter's similis 

 and brevicuneata. They possess six arms on each postradial series, the number charac- 

 teristic of similis, and the IBri are entirely visible, which according to Carpenter is 

 characteristic of brevicuneata. In the relative length of P 4 , which was also considered 

 as of importance in differentiating these two forms, they show the relationship sup- 

 posedly characteristic of brevicuneata, in which P is markedly smaller than P 3 . In 

 its turn, P 3 is as long as P 2 . Not rarely P 2 reaches 15 mm. in length, so that Carpenter 

 was not correct in saying that brevicuneata in general has shorter lower pinnules than 

 similis, in which, according to him, P 2 is 14 mm. long. Hartlaub remarked that the 

 differences between brevicuneata and mmilis, if there are any constant differences, 

 would be confined to the relative length of P 4 . 



I examined the two specimens at the Hamburg Museum in 1910. Each has 30 

 arms 80 mm. long. There are 22 or 23 cirrus segments. P 2 is 10 to 12 mm. long, 

 rather slender, and composed of 26-37 segments. Though there is no apparent 

 enlargement of the lower pinnules on the outermost arms of each postradial series, 

 these are much longer, reaching 18 mm. in length. 



In the three specimens from Ebon, Marshall Islands, which Hartlaub recorded as 

 brevicuneata, the sides of the IBr and IIBr series, as in those he described from Amboina, 

 show either no marginal thickening and lateral flattening or only here and there slight 

 traces of these features. Hartlaub recalled that the specimen from Amboina in the 

 Leyden Museum and the specimens from Mortlock Island that he had studied have 

 postradial series with strongly flattened sides and marginal thickenings. In the 

 specimens from the Marshall Islands there are no inner IIIBr series. The color of the 

 three specimens is very different. One is uniform light brown. Another is light gray- 

 brown in the central portion, darker in the outer portion. The third is uniform dark 

 brown. 



