1885.] PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 633 

 Dimensions of two young specimens. 



Total length millimeters . . 



Length of stem do 



Number of iuternodes 



Number of intemodal joints 



Length of cirri millimeters.. 



Number of joints in cirri 



Diameter of calyx (top of first radials) millimeters. . 



Height from point of attachment of stem to upper edge of third radi- 

 als t millimeters.. 



Number of free arms 



Length of arms millimeters.. 



Number of joints in arms 



In the smaller specimen the interarticular pores extend through 

 the upper three or four iuternodes, and in the latter through the same 

 number; in the former the radials are proportionally longer; thebasals 

 are comparatively large in both. In the smaller each ray divides regu- 

 larly into two arms: in the larger into 5 or 6 arms each, with two dis- 

 tichals and two palmars. 



There are in the collectipn of 1884 two interesting specimens that 

 appear to be modifications of this species in the direction mentioned by 

 Carpenter (loc. cit, p. 311), with respect to two specimens collected by 

 the Coast Survey steamer Blake off Martinique and Barbadoes; but the 

 extent of the variation in our specimens is much greater, though mainly 

 limited to the lower brachials of the arms. One specimen came from 

 station 2134, south of Cuba, depth 254 fathoms; the other is trom a. 

 depth of 300 fathoms, at station 2155, off Havana. For convenience in 

 describing them we will designate the former A, the latter B. With 

 specimen A one typical example of P. Mulleri was collected, and B came 

 from the same locality where the largest hauls of this species were 

 made, though it was the only specimen obtained at that particular sta- 

 tion. Both specimens are in very perfect condition, A being slightly 

 larger than B. In A the stem is 168°^™ long, with 19 internodes, and 

 terminates with a nodal joint ; the diameter of the stem is 4.2™™, the 

 number of internodal joints 7. The stem is very decidedly pentagonal 

 in A, but in B is more rounded; in both, the joints are of subequal 

 length ; the cirri in A are about 34™™ long, and consist of 33 joints 

 each. 



The basals are very small, and very widely separated in A, but in B 

 they are somewhat larger and touch slightly exteriorly. There are three 

 radials on each ray of both specimens, in A being comparatively low 

 and broad; the diameter of the calyx at the top of the first radials in A 

 is 9™™. In the latter there are 30 arms, each ray dividing regularly into 

 6, the arrangement being 2. 1 ; 1. 2; there are two distichals and three 

 palmars; the longest free arm measures 103™™, and consists of 88 joints. 

 The surfaces of all the joints of the calyx and arms, up to and including 

 the first brachial, are slightly more raised, and appear harder and 



