^{page 243 note *} John V. Thompson, “Memoir on the Pentacrinus europæus.” Cork, 1827.

^{page 244 note *} Busch, “Beobachtungen über Anat. und Entwickel. einiger Wirbelosen Seethiere.” Berlin, 1851.

^{page 244 note †} Thompson, loc. cit. Since reading the present paper, I met with an abstract of a paper on the “Embryogeny of Comatula rosacea,” by Professor Wyville Thomson, in the “Proceedings of the Royal Society of London” for Feb. 5, 1863. In this paper Professor Thomson gives us the results of a series of valuable observations in which he has traced the development of the larva beyond the stage at which it was left by Busch, and has further elucidated its earliest stages. He has not, however, carried it up to the point which it is the object of the present paper to describe; while the very careful and complete researches of Carpenter, referred to below, would seem to start from a point a little in advance of that here described.

^{page 245 note *} Dr Carpenter informs me that he has detected in an early stage of the larval Comatula, an unsymmetrical “anal” plate, which he regards as one of a first series of inter-radials (the rest of this series being usually abortive), and which is afterwards lifted by the development of the anal funnel into a much higher position. I have sought in vain for this plate in my specimen, and am of opinion that in the stage to which this specimen belongs, the plate does not exist. It is quite possible, however, that though it has here escaped detection, it may yet be found in specimens better suited for observation.

^{page 246 note *} It should be borne in mind, that while the basal zone of Platycrinus appears to depart from the type, by having only three distinct basalia, these pieces easily admit of a further analysis into the typical number five.

^{page 246 note †} From a letter which I have received from Dr Carpenter since the above paragraph was printed, I find that he has instituted a nearly similar comparison between the calyx of the young Comatula and that of the adult typical crinoid.

^{page 247 note *} Mém. de l'Acad. Roy. des Sciences, 1755.

^{page 247 note †} Memoir on the Pentacrinus europæus, Cork, 1827; and afterwards in the “Edinburgh New Philosophical Journal,” 1836.

^{page 248 note *} Palæontology of New York.

^{page 248 note †} The term “axillary” is here used in the sense in which it is employed by de Koninck.

^{page 248 note ‡} I cannot, with Römer, Pictet, and Bronn, regard Stephanocrinus as a cystidian, a view opposed not only by the numerical law of its parts, but by the structure of its roof, and the position of its arms as determined by Hall, from which we must infer a considerable development for the ambulacral zone, a character inconsistent with cystidian morphology. Dujardin with more reason places Stephanocrinus in his family of Haplocrinidœ. The so-called ovarian pyramid of this genus seems to me much more probably an anal orifice.

^{page 249 note *} Ueber Eugeniacrinites caryophyllatus in Neues Yahrbuch für Mineralogie, &c. 1855. P. 669.

^{page 251 note *} See Römer, Monographie der Blastoideen. Archiv. f. Naturg. 1850.