ME. P. H. CAEPENTEE ON THE GENUS ACTINOMETEA. 5 



Laniarck included eight species in bis new genus Comatula. In only three of these is 

 the mouth at or near the centre of the disk, viz. C. mediterranea (= Stella decacnemus 

 rosacea, Linck), C. carlnata(= Antedon gorgonia, T?rem. ?), and C. adeonce. 



In all the other five species described by Lamarck, viz. C. Solaris, C. brachiolata, 

 C. rotalaria, C. fimbrlata (= Stella chinensis, Petiver), and C. multiradiata (= Caput- 

 Medusce brunnum, Linck), the mouth (as I know from examination of the collection of 

 Comatula? in the Paris Museum, which still contains many of Lamarck's original spe- 

 cimens) is nowhere near the centre of the disk, which is occupied by the anal tube, but 

 is excentric, or even marginal. At the same time the five primary groove-trunks do not 

 converge towards the centre of the disk, as in Antedon rosacea (Com. mediterranea, Lam.) 

 (PL I. fig. 1), but they unite more or less completely into a horseshoe-shaped furrow, at 

 one point of which is situated the excentric mouth (PL I. figs. 2-5). 



This type will be described further on, under the name of Actinomelra. Lamarck, who 

 found it in more than half of the species constituted by him, seems to have regarded 

 it as common to all ComatuLw His description of it is worth quotiug, as it is the first 

 notice of a true Actinometra that I have been able to find. lie says 1 : — "Le disque 

 iuferieur ou ventral offre un plateau orbiculahv plus large que le dorsal, entoure de rayons 

 simples, cirreux. Pres de la circonference de ce plateau, on apercoit un sillon irregu- 

 lierement circulaire qui s'ouvre sur la base des rayons pinnes, et se propage le long de 

 leur face inferieure, aussi que de celle des pinnules. Cc sillon neanmoins, ne s'approche 

 point de la bouche [i. e. the anal tube] et ne vient point s'y reunir, comme cela a lieu 

 pour la gouttiere des rayons dans les Asteries. Au centre du disque iuferieur ou ventral 

 des Comatules la bouche, membraneuse, tubuleuse, ou en forme de sac, fait une saillie 

 plus ou moins considerable suivant les especes." 



Although Antedon and Alecto were both constituted previously to Comatula, yet 

 Lamarck's authority was sufficient to establish the latter name, and to bring it into 

 general use, though Cuvier adopted Leach's genus Alecto, and used it in preference to 

 Comatula. The latter, however, was more generally employed by all subsequent 

 observers (who pointed out Lamarck's error respecting the position of the mouth) 

 thenceforward till the time of Johannes Miiller. 



(§ 5) During this period the skeleton both of the recent and of the fossil Crinoids was 

 made the subject of careful investigations by Miller 3 and Goldfuss 3 . The latter 

 author divided his class Stellerites into two Orders : — (a) Stilasteritse, or Gestielte 

 Seesterne ; and (b) Asterites liberi, or Preie Seesterne. The former he again divided into 

 Articulata and Inarticulata, placing in the first group a number of fossil Mesozoic 

 Crinoids, viz. Eugeniacvinites, Miller, Solanocrinites, Goldf., Pentacrinites, Encrinites, 

 and Ajuocrinites. 



In his descriptions of these genera he adopted and considerably improved the some- 

 what inapplicable system of nomenclature, introduced by Miller for the parts of the 

 skeleton of the fossil Crinoids and of Comatula. 



Portions of his diagnoses of Eugeniacrinites and Solanocrinites are of considerable 

 interest, both zoologically and morphologically. Of the former, he says 4 : — 



1 Tom. tit. p. 532. ' ; Loc. cit. 3 Petrefacta Germanic, i. (Dusseldorf, 1826-35). 4 Turn. tit. p. 102. 



