166 THE VOYAGE OP H.M.S. CHALLENGER. 



twenty slender joints, and are only about 6 mm. long. The following pinnules increase 

 gradually, both in length and in stoutness, reaching 15 mm. in the outer parts of the 

 arms. The two basal joints are flattened and trapezoidal, with incurved edges. Ovaries 

 long and fusiform, extending over the greater part of the length of the lower pinnules. 



Disk naked or nearly so ; sacculi abundant. 



Colour in spirit, — light reddish-brown. 



Diameter of centro-dorsal 5 mm.; spread about 17 cm. 



Localities. — H.M.S. "Porcupine," 1869. Cold area? Two specimens, with Myzo- 

 stoma cirriferum. 



H.M.S. "Triton," 1882. Station 4; Lit. 60° 22' 40" N. and 60° 31' 15" N., long. 

 8° 21' W., and 8° 14' W. 327 to 430 fathoms; stones, mud; bottom temperature, 31°-5 

 to 30 o, F. One specimen. 



Remarks. — The two individuals of this remarkable type which were obtained by the 

 "Porcupine" in 1869, seem to have been regarded as belonging to Antedon eschrichti, 

 and so remained unnoticed, while their locality was not recorded. They did not come 

 into my hands till 1883, when I also received the Comatulse dredged by the "Triton" 

 and " Knight Errant." The former collection included another example of the same type 

 from the " cold area," and as its nearest ally is the Arctic species Antedon prolixa, the 

 " Porcupine " specimens may be safely referred to one of the "cold area" stations. All 

 three individuals agree very closely in their general features and especially in the curious 

 dimorphism of the cirri, which is almost as marked as in Antedon phalangium. A good 

 example of the mature smooth and long-jointed cirrus is shown in PL XXVIII. fig. 4, 

 and some of its younger stages are seen in fig. 5 round the upper edge of the centro- 

 dorsal. But the cirri attached nearer the dorsal pole are somewhat different in appearance 

 (PL XXVII. fig. 21). Many of them are comparatively short, with only about twenty- 

 five joints, which are as wide as or wider than long and have slightly expanded ends so as 

 to overlap their successors. This is especially marked on the dorsal side, which is produced 

 into a sharp forward projecting spine. These characters seem to disappear, however, as 

 the cirri increase in age and develop additional joints (PL XXVII. fig. 22), so that 

 eventually they are not very markedly different from the smooth and long-jointed cirri of 

 the other type. 



Antedon hystrix has a considerable amount of resemblance to Antedon prolixa, 

 which was obtained in Eobeson Channel by Nares's Arctic Expedition in 1875, and was 

 subsequently well described by Sladen. 1 Before giving a new name to the " Porcupine" 

 and "Triton" specimens, I compared them carefully with Sladen's type, and came to the 

 conclusion that they should be regarded as distinct. Subsecment research has justified 

 this view. I have elsewhere described two specimens of Antedon prolixa which were 



1 Op. tit., p. T7, pi. vi. figs. 7-10. 



