194 



BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



In this specimen all but 1 of the IIBr series are 2, while of the 10 IIIBr series 

 present 5 are 2, 3 are 3 (2 + 3), 1 is 4 (3 + 4), and 1 is 5 (4 + 5); the 6 IVBr series are 

 all 3 (2 + 3). In the 36 arms the first syzygy is between brachials 2 + 3 in 29, between 

 brachials 3 + 4 in 6, and between brachials 15 + 16 in 1. 



This specimen exhibits an unusual complex of characters. The division series 

 of 2 are the division series of Comatella, representing the so-called compound type 

 of arm division, and not the usual type of division series of two ossicles as illustrated 

 by the genus Dichrometra. A large portion of this specimen, therefore, would be 

 unhesitatingly referred to some species of Comatella were it studied without regard 

 to the remaining portions. The division series of 4 (3 + 4) is of the type charac- 

 teristic of the subfamily Comasterinae, and in particular of the genus Comanthus. The 

 division series of 5 (4 + 5) is a variant of no particular significance. The syzygies 

 between brachials 2 + 3 are those of the genus Capillaster and are normal for that 

 genus only; those between brachials 3 + 4 are normal for the species of Comas- 

 terinae only when occurring on the inner arms, but when found on the outer arms 

 are normal both for the species of Comasterinae and for the species of Comatella. The 

 syzygy between brachials 15 + 16 is a variant. 



Analyzed on the basis of the characters furnished by the division series and the 

 arms, we find this specimen to represent the genus Capillaster, the genus Comatella, 

 and the subfamily Comasterinae in the following proportions: 



A specimen without locality in the British Museum has 17 arms about 40 mm. 

 long. Three of the IIBr series are 2, and 2 are 4 (3 + 4); each of the latter bears 

 internally a IIIBr 3 (2 + 3) series. The IIBr 2 series may be immediately followed 

 by a syzygial pair (the normal first syzygial pair) or the first syzygy may be between 

 brachials 2 + 3, these two types of proximal arm structure being of about equal 

 frequency. There are 21 cirrus segments. Half of this animal would certainly be 

 identified as Comatella maculata, the other half as Capillaster multiradiata. 



In another specimen without locality in the British Museum 5 of the IIIBr series 

 are 1, and 1 is 3 (2 + 3). 



The specimen from Ruk, Caroline Islands, described by Hartlaub and reexamined 

 by myself at Hamburg, has 28 arms; the cirri are XXI, 24-28. The brachials are 

 short discoidal with strongly produced distal edges. Of the 10 IIBr series 8 are 

 2 (1 + 2) and 2 are 4 (3 + 4). The IIBr 2 (1 + 2) series are all followed by IIIBr series ; 

 of these IIIBr series 1 is 4 (3 + 4) and the remainder are 3 (2 + 3). The 2 IIBr 4 

 (3+4) series are not followed by IIIBr series. The first brachial syzygy is in all 

 cases between brachials 2 + 3 ; the second varies from between brachials 26 + 27 to 



