DEVELOPMENT OF AJfTEDON (COMATULA, LAMK.) EOSACEUS. 689 



mata, according to " the modifications of their organs and modes of progression." He 

 does not enter into any explicit justification of the claims either of the Ckinoidea or of 

 the OrmuRlDA to the ordinal rank here first assigned to them ; but contents himself 

 with remarking that " as an explanation of the true nature and relation of the Echino- 

 dermatous tribes, I prefer it to any arrangement at present used, and have accordingly 

 followed it throughout this work." There can now be no doubt that Professor Fokbes 

 was completely justified in separating the Ceinoidea from the Stelleeida Avith which 

 they had been previously associated ; since they differ entirely from the Asterida and 

 the Oj)hiurida in the conformation both of their digestive and of theu* generative appa- 

 ratus ; whilst theu" resemblance to those groups is only such as springs from the general 

 disposition of the parts of their skeletons, the fundamental homologies of which are 

 altogether diverse. And in accordance with his views, a rank corresponding to that of 

 Echinida and Asteeiada has been assigned to the Ceinoidea by the general consent of 

 subsequent systematists ; as D'Okbigny', Van^ dee Hoeven% P:ctet^ Beonn^ De 

 KoNiNCK and Le Hon', and DuJAEDlN^ 



The account which Professor Edwaed Foebes gave of Cmnatula rosacea appears to 

 have been written without any knowledge of the previous anatomical investigations of 

 Heusingee, and was issued before those of Professor MUllee had been communicated 

 to the Berlin Academy. It is for the most part confined to the external characters of 

 the animal, which are in general correctly described, though not with the minuteness 

 which could only be attained by a more elaborate microscopic investigation than Pro- 

 fessor Foebes seems to have bestowed upon the details of its sti-ucture. He rightly 

 apprehended the relative characters of the mouth and anus ; and with respect to the 

 latter he remarks, "This curious vent has been mistaken by many authors for the 

 mouth, and has greatly puzzled others ; and M. de Blainville suggested that it might 

 be connected with the functions of respiration or generation : but any one who examines 

 the Comatula alive, or dissects a specimen well preserved, will not doubt it is a true 

 vent." He made, however, a most extraordinary mistake in regard to the ovaries; for 

 notwithstanding the veiy explicit statement of Mr. J. V. Thompson (which he quotes) 

 as to the liberation of the ova from conceptacles formed by the swelling of the pinnae, 

 he affirms that only spermatozoa are formed in these conceptacles, and that the real 

 ovaries are certain " round brown dots, placed in regular rows and at regular distances 

 along the margins of the canals, on the body, the arms, and the pinnoe." What is the 

 true nature of these spots, is a question which will be considered hereafter ; it may be 

 positively affirmed, however, that they are not the ovaries, since the production of the 



' Cours Elementaire de Paleontologie et de Geologie Stratigraphiques. Paris, 1849. 

 ' Handbook of Zoology, translated by Professor Clakk. London, 1856. 



• Traite de Paleontologie, 2'i'n'" Ed. Paris, 1857. 



■* Die Klassen und Ordnungcn des Thicr-Ecichs. Zweiter Band. Leipzig und Heidelberg, 1860. 

 ' Eecherches sur les Crinoides du Terrain Carbonif^re de la Belgiquc. BruxcUes, 1854. 



• Histoire Naturelle des Zoophytes Echinodermes. Paris, 1862. 



5b2 



