136 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Hartlaub remarked that the character of the pinnules varies with that of the arms 

 that bear them. The pinnules range from those with a number of broad segments 

 bearing a high spinous carinate process, as in the variety alata, to those in which 

 the segments are neither markedly broadened nor bear carinate processes. 



A constant feature is a number of proximal pinnules which decrease in length 

 and are slender and flagellate with a more or less extensive comb on their very slender 

 and whiplike distal portion. They are composed of short segments which are in 

 contact only at one point so that the profile of both edges, but especially the distal, 

 is serrate. These pinnules vary rather considerably in their details. The decrease 

 in length may be very gradual, or P 2 may be abruptly shorter than Pj. This last 

 condition occurs in 2 specimens from Blake station 294, one referable to pulchella, the 

 other to alata. 



The length of these pinnules naturally is proportionate to the size of the animal, 

 though it varies in individuals of approximately the same size. Thus PI in the 12- 

 armed brown specimen from Blake station 45Ag. is quite 20 mm. long with about 

 50 segments, while the length of the same pinnule on an even larger specimen from 

 Blake station 148 is only 17 mm., and the pinnule is composed of only about 40 

 segments. 



The comb of P! has 15-20 teeth, of which the points may be sharp or blunted. 

 Traces of a comb are sometimes to be made out as far as P 7 , while on other specimens 

 the combs do not extend beyond P 5 . But the comb on P 6 may have as many as 

 about 14 teeth without the following pinnules having the slightest suggestion of a 

 comb. 



In the variety planata P 5 is usually without a comb. 



Hartlaub notes that the form of the pinnule segments recalls that seen in Comac- 

 tinia meridionalis. In different specimens the lateral processes and the amount of 

 the development of spines is variable. The brown 12-armed specimen from Blake 

 station 45Ag. has the segments of the first 12 pinnules on each side of the arm, except 

 for the first 2, with stout carinate processes bearing a few large spines. There are 

 spines also on the segments of the following pinnules, but the processes are only 

 slightly developed. 



The relatively smoothest pinnules are found in the variety planata. The proc- 

 esses here are limited to the second and third segments of the lower pinnules, there 

 being on the following segments instead of them a small group of spines. The 

 spines are minute and only visible under a strong magnification. 



The distal pinnules are only moderately long. 



The pinnules are commonly united by a membrane which incloses their basal 

 segments and extends outward from these. This webbing of the pinnules is most 

 developed in the variety alata and is absent in the variety planata. It is very variably 

 developed in true pulchella. 



In the largest specimens the disk has a diameter of from 16 to 18 mm. It is 

 sometimes entirely covered with thick calcareous nodules, and sometimes naked, or 

 only beset with conical calcareous papillae on the anal tube. 



Sometimes in the variety alata the whole anal area as far as the anal opening is 

 covered with large calcareous warts, while in the other interradial areas these are 



