THE RECENT CRINOIDS OF AUSTRALIA — CLARK. 779 



The preceding description was drawn up fi'om an examination 

 of nineteen specimens, all from the type locality. 



Differential Characters. — The only species with which this 

 needs comparison is 0. adeonoi, with which it agrees in the general 

 stoutness of its build and in the larger size of P^ over Pg. It is 

 smaller and has fewer cirrus segments than that species, however, 

 and they lack the curious bidentate structure dorsally ; as a 

 whole, also, the cirri are considerably stouter than those of 0. 

 adeonce. There is no swelling of the genital pinnules in 0. 

 adeonm. 



There can be no confusion between these two forms and 0. 

 carpenieri and 0. serripirma, as the latter are slender and delicate 

 creatures with a small and delicate P^ and much enlarged and 

 stiffened Pj, the latter hiving stout lateral processes on its 

 segments. 



Specimens Examined. — Off Wollongong, 55-56 fathoms — Nine- 

 teen specimens. 



These are the original specimens upon which the species was 

 founded. 



Remarks. — 1 cannot see any grounds for believing that this 

 form may eventually turn out to be Lamarck's adeonce as suggested 

 by Dr. Clark; it is much smaller than that species, and the 

 pinnules could not possibly be described as long, nor are the three 

 or four first the longest. In general appearance it is curiously 

 similar to Analcidometra caribbea^ from the Carribean Sea; it 

 is about the same size, the lower pinnules are moi'e or less 

 similar in shape and proportions, and the genital pinnules are 

 similarly expanded. 



Family T R P I O M E T R I D ^, ^. ^. Clark. 



Genus T R O P I O M E T R A, ^. ^. Clark. 



Tropiometra, 1907, A. H. Clark, Smiths. Miscell. Coll. (Quarterly 

 Issue), vol. 50, p. 349 (Comatula carinata, Lamarck, 1816). 

 Di^erenlia.1 Characters. — la the genus Tropiometra the I Br 

 series and the first two brachials are large and broad, in lateral 

 apposition, and somewhat flattened laterally, but the remaining 

 brachials are exceedingly short ; the dorsal surface of the arm 

 may be smooth, or there may be a tubercle developed in the 

 middle of the dorsal side of each brachial, which sometimes rises 

 into a very high carination. The cirri are stout with from 



5 Oligomttra caribbea, 1908, A. H. Clark, Proc. U.S. Nat. Mus., vol. 34, 

 No. 1608, p. 238. 



