560 



THE VOYAGE OF H.M.S. CHALLENGER. 



of this character to far out on the arms. It is well shown in some parts of fig. 1 on 

 PI. XLVIII. 



It was on a proof copy of this plate that I found the MS. name Metacrinus in Sir 

 "\Vy\dlle's own handwriting ; and I have therefore taken the opportunity of associating 

 this elegant species with his memory. It is one of some importance on account of its 

 occurrence at two such widely separated localities as the Kermadec Islands (Station 170a) 

 in lat. 29° 45' S., and the Meangis Islands (Station 214) in lat. 4° 33' N. The two 

 specimens obtained at the former Station are both of very considerable interest. The 

 stem of the larger one, which is 25 cm. long, is broken at the thirty-sixth node, the inter- 

 nodes being shorter than in the more northern individuals, as seven joints are the 

 exception and not the rule. As in so many other cases, this stem tapers gradually down- 

 wards, being almost 5 mm. wide immediately below the calyx, and less than 3 mm. at 

 the lowest node, just above which the diminution in size is most rapid. 



The other specimen obtained at Station 170a is a young individual, with a head not 

 more than 55 mm. long, and less than sixty joints in the free arms. The attached portion 

 of the stem, which is 185 mm. long, is a trifle over 3 mm. wide just below the basals, 

 which are relatively very large and prominent. Its diameter decreases slightly to about 

 the fifth node, and then slowly increases again till the sixteenth node, where the stem 

 widens rather suddenly. It reaches 4 mm. at the last joint immediately below the 

 twenty-seventh node. The ornamentation of this stem is less well defined than in the 

 older specimen from the same locahty. In fact there is a good deal of individual variation, 

 some of the stems from Station 214 ha\'ing very well defined horizontal ridges (PL XLVII. 

 figs. 1, 2), while they are rather inconspicuous on the figured specimen (PI. XLVIII. fig. 2). 



One individual presents a curious amount of variation in the character of the rays. 

 Three are normal, consisting of six joints, of which the second and fourth are syzygies ; 

 but on one of these the usual pinnule on the epizygal of the fourth brachial is 

 missing, though that on the next joint is present. Another ray consists of seven 

 joints, the fifth and sixth of which bear pinnules on the same side ; while the fifth ray 

 has eight joints with no pinnule on the sixth. 



8. Metacrinus costatus, n. sp. (PL XLVII. fig. 13 ; PL XLIX.). 



Dimensions. 



Length of stem to the twenty-fourth node, . 



Diameter of stem, .... 



Longest cirrus (forty-five joints). 



Diameter of calyx, .... 



Length of arm (one hundred joints beyond the palmar axillary), 



Length of pinnule on first distichal (seventeen joints), 



Length of first pinnule after palmar axiUary (twenty joints), 



