Report on tiie Echiiioderms of North-East Greenland. 281 



Arctica. p. 144). Upon the whole I think then we can safely assert 

 that what has been recorded as Cue. minuta will prove to be either 

 Cucumaria glacialis or young specimens of Cucumaria frondosa. 



The question still remains, whether Lu tken was right in iden- 

 tifying his specimens with the Holothuria minuta of Fabricius. I 

 think he was not. Fabricius' statement that it has 12 tentacles 

 does not agree with Lütken's supposition; further, the drawing 

 reproduced by Lut ken (loc. cit.) seems to show a double circle of 

 tentacles. These facts would suit much better to the young Phyllo- 

 phorus peUucidus {Orcula Barthii). It is true, this species has 15 

 tentacles, not 12 as stated by Fabricius; but it is certainly more 

 easily understood that Fabricius has seen only 12 tentacles in a 

 species where the normal number is 15 (some of the tentacles may 

 have been smaller than the others, as is not seldom the case in 

 Phyllophorus, according to Östergren) than that he should have 

 counted 12 tentacles in a species which has only 10. — Fabricius 

 also does not state anything about the two radii having fewer tube- 

 feet than the three others, in accordance with the fact that in the 

 young Phyllophorus the radii are equally developed. One more fact 

 speaks for the supposition that Holoth. minuta Fabr. is the young 

 Phyllophorus peUucidus, namely its habits. According to Fabricius 

 it is found ''under stones on sandy bottom, burrowing in the ground, 

 though not fixed, but free". This burrowing habit decidedly suits 

 better to Phyllophorus than to Cue. frondosa. 



It is thus very probable that Holothuria minuta Fabricius is the 

 young Phyllophorus. The definite proof cannot be given at present; 

 but it would probably be rather easy to find in suitable Greenland 

 localities specimens living in the sand under stones, as described 

 by Fabricius, and thus to settle the question definitely. For the 

 present we must rest satisfied with the statement that it is certainly 

 no separate species, but probably identical with Phyllophorus peUu- 

 cidus (Barthii). 



In the place quoted (p. 9) Lu tken mentions another young 

 Cucumaria resembling a young C. frondosa, but having small calcare- 

 ous corpuscles in the skin. There can be no doubt that this is like- 

 wise С frondosa. 



Lütken refers to Cucumaria assimilis Dub. & Ivor, as a species 

 which ought to be compared with С minuta. Ludwig (Arkt. u. 

 subarkt. Holothurien. Fauna Arctica. p. 148) regards this species as 

 a synonym of Cue. lactea (Forbes). In my opinion it can scarcely 

 be doubted that it is really synonymous with C. frondosa. The 

 calcareous corpuscles agree exactly with those of С frondosa, whereas 

 they differ considerablj' from those of C. lactea, as is well represented 



