122 



THE VOYAGE OF H.M.S. CHALLENGER. 



Disk 7 mm.; spread about 20 cm. 



Localities. — Station 170a, July 14, 1874; near the Kermadec Islands; lat. 29° 45' 

 S., long. 178° 11' W.; 630 fathoms; volcanic mud; bottom temperature, 39° - 5 F. 

 Several specimens. 



Doubtful. — Station 175, August 12, 1874 ; near Kandavu, Fiji; lat. 19° 2' S., long. 

 177° 10' E.; 1350 fathoms; Globigerina ooze ; bottom temperature, 36° F. Some arm- 

 fragments only. 



Remarks. — This species and the following one (Antedon incisa) are sharply 

 distinguished from the preceding members of this group of ten-armed Antedons by their 

 smooth, stout cirri, and the peculiar expansion of the lower joints in the proximal and 

 middle pinnules (PL XXI. fig. 2). The only other Antedon in which the latter character 



Fig. 2. — Antedon basicurva, x 3. A. Side view of the calyx and arm-bases after the removal of three rays, so as to show 

 the sides and inner faces of the other two. The two outer radials, two lower brachials, and in a less degree also the 

 third and fourth, have their outer sides flattened against one another. The genital pinnules have the third and fourth, 

 and sometimes the fifth joints greatly expanded, but the following ones are smaller. B. The lower part of an arm from 

 its inner side, to show the flattened inner faces of the first three brachials, including both the hypozygal and the 

 epizygal of the third. 



is similarly develojaed is a tridistichate species, Antedon inzequalis (PI. LI. fig. 2), which 

 occurs at the same two stations (Stations 170a and 174) as Antedon incisa, Antedon basi- 

 curva having been found at the former only. It is possible too that Antedon basicurva 

 and Antedon insequalis were obtained at Station 175 j 1 though there appears to be much 

 doubt upon this point. But whether this be the case or not, it is clear that the pecu- 

 liarity in question is a local one and limited to this particular region of the South Pacific. 



1 Only two Comatulce are recorded in the Station Book as having been found at this locality ; and as the depth is 

 considerable (1350 fathoms), I have little doubt that they are the two small forms of Antedon breviradta and Antedon 

 acutiradia already described. The arms of the latter were all loose, however, and it is quite possible that the few arm- 

 fragments of Antedon basicurva may have been amongst them ; but no calyx of this species was obtained. 



