244 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The specimen from Dr. Merton's station 10 is small. The cirri are XXIII, up 

 to 42, relatively very long, 19 to 23 mm. in length. The first two segments are 

 broader than long, the third and fourth are about as long as broad, those following 

 about as far as the twelfth are very markedly longer than broad, and from that point 

 onward the segments are broader than long. The spines on the distal segments are 

 sharp and prominent, and the cirri are strongly compressed laterally in the distal 

 half. The 27 arms are only about 38 mm. long. All the division series following 

 the IIBr series except for two are 2. P D is 11 mm. long and is composed of 22 segments 

 of which the proximal are relatively less broad than in the specimen from station 11. 

 PI is about 12 mm. long and composed of about 28 segments. P 2 is markedly shorter, 

 while P 3 is scarcely half as long as Pj and is composed of about 12 segments. The disk 

 is 10 mm. in diameter. The calyx and arms are dorsally light flesh color (in alcohol 

 grayish white), the pinnules centrally being more or less violet; the cirri are dark 

 violet. 



Remarks. Reichensperger said that because only two specimens of this fine 

 species were previously known he had given a rather detailed account of some of the 

 features of his two specimens with particular reference to the great difference in size 

 between them. Of the smaller specimen he said that there is no possibility of doubt 

 regarding the correctness of the specific determination because of the general habitus, 

 the division series, the structure of the arms and other features. He noted that this 

 individual shows very convincingly how little weight may at times be attributed 

 to the relative length of the segments of the cirri and lower pinnules. He remarked 

 that he was under the impression that in the crinoids increase in length often out- 

 stripped, as it were, increase in width, and that as a result during development the 

 relative proportions of the segments, so far as regards length and breadth, reversed 

 themselves as we not rarely find to be the case with other features. Naturally, there- 

 fore, in the crinoids the systematic worth of characters of this sort, which heretofore 

 have often been very highly regarded, must be discounted, and they can only be taken 

 into consideration in a relative way. 



We know far too little about the growth changes in the comatulids, as apart from 

 variations due to other causes, to be able to say anything definite one way or another 

 at the present time. But Dr. Reichensperger has raised an interesting point and one 

 worthy of intensive study. 



The species of Heterometra are among the most puzzling of all the comatulids, 

 and features that in other genera we believe may be confidently relied upon, such as 

 the character of the cirri and the relative proportions of their segments and the rela- 

 tive proportions of the segments in the proximal pinnules, in some species of Hetero- 

 metra, at least, are wholly unreliable. Tliis is well illustrated by H. crenulata, which 

 seems to behave quite as described by Dr. Reichensperger for H. nematodon, and 

 furthermore seems to be most unstable in the same region the Aru Islands. 



Localities. Bowen, Queensland [Hartlaub, 1890, 1891; A. H. Clark, 1907, 1909, 

 1911, 1912, 1915, 1918; Reichensperger, 1913; H. L. Clark, 1921] (1, H. M.). 



Alert; Port Molle, Queensland; 22-36 meters [Bell, 1883; A. H. Clark, 1913] 

 (1, B. M.). 



Aru Islands; Dr. H. Merton's station 10; north of Penambulai; 8 meters; stony 

 bottom; April 2, 1908 [Reichensperger, 1913]. 



