DEVELOPMENT OF iJNTEDOX (COMATULA, LAMK.) EOSACEUS. 691 



here repeat them. As he justly remarks, it would appear from Professor Sars's descrip- 

 tion that the pedunculate condition is much more prolonged in A. Sarsii than in 

 A. rosaceus; the animal being only distinguishable by the persistence of its stem from 

 an adult Anfedon. 



Early in 1863 Professor Allman communicated to the Royal Society of Edinburgh' 

 a Memoir " On a Prebrachial stage in the development of Comatula" based on the 

 observation of a single specimen which he had obtained on the coast of South Devon ; 

 and he was the first to publish tlic very interesting fact that the plates first formed in 

 the Pentacrinoid larva are the circlet of hasals and the circlet of orals superimposed 

 on them, the former constituting the calyx, and the latter forming its pyramidal roof; 

 the only vestige of the radials, which are aftenvards to constitute the essential part of 

 the skeleton, being a set of five minute plates intercalated between the upper angles of 

 the basals. This disposition he compares with that of the plates in certain fossil 

 Crinoidea', which in his opinion permanently represent a condition that is transitory 

 in our Pentacrinoid larva. His account of the tentacular apparatus, however, bears 

 evidence of the insufficient opportunities for observation afforded him by the possession 

 of a single specimen ; and I feel bound to state that having myself verified Professor 

 Wyville Thomson's descriptions, — which are based on frequently-repeated observations 

 made upon an ample supply of specimens, and these not merely in the phase of develop- 

 ment which fell under Professor Allman's notice, but in all the preceding and subsequent 

 stages, — I am quite satisfied of their correctness on all those points in which they differ 

 from the descriptions of Professor Allmak. 



The foregoing constitute, I believe, all the contributions hitherto made to our 

 acquaintance with the structure and physiology oiAntedon ; and it only remains for me to 

 notice two recent works, one on the Crustoidea, the other on the Echixodermata generally, 

 in which its relations to the Crinoids and to other Echinodcrms are discussed with all 

 the advantage of more advanced knowledge. 



The first of these is the memoir of MM. L. de Koninck and H. le Hex, entitled 

 " Recherches sur les Crinoides du Terrain Carbonifere de la Belgique"^, which is much 

 more comprehensive than its title would indicate, since it contains an elaborate History 

 of the progress of knowledge as to the Crinoidea generally (to which I have already 

 had occasion to refer, p. 675), and a philosophical investigation of their Zoological 

 relations, and of the principles on which the classification of the group should be 

 founded. Their inquiries have led them to a modification of the nomenclature of 

 Professor MUller, which will, 1 believe, be found practically convenient, and which, 

 therefore, I shall follow in my own description. The only addition to our knowledge 

 of the recent Crinoidea which this memoir contains, is furnished by a previously 

 unpublished communication from M. Duchassaing to M. Michelin, accompanying a 



' Transactions of the Eoyal Society of Edinburgh, vol. xxiii. p. 241. 

 ' Me'moires de r Academic Eoyale dc Bclgiquc. Bruxellcs, 1854, 



