388 Mr. P. H. Carpenter. Preliminary Report upon [Mar. 6, 



these are not too common. A few specimens are known from the 

 Gault, Greensand, and Batk Oolite, while the Jurassic beds of the 

 Continent have yielded Solanocrinus and a few little known forms 

 from the Solenhofen slate (Pterocoma, Saccocoma). 



It should be noted, however, at the same time, that Tertiary Coma- 

 tulce are also very rare, Philippi's Alecto alticeps, from the Sicilian 

 Tertiaries being the only one which I can call to mind. This is 

 scarcely surprising when it is remembered that the distribution of 

 modern Comatulce is chiefly in the tropics and temperate zones, there 

 being but few Arctic or sub- Arctic species. The Australian Tertiaries 

 might possibly yield different results. 



The voyage of the " Challenger " has settled two curious questions 

 in connexion with the Crinoids, the origin of which is due to Loven. 

 They refer to Hyponome Sarsii, a so-called recent Cystid, and to 

 Phanogenia, a supposed new genus of the Comatulidce. Hyponome 

 turns out to be nothing more than the disk of a Comatnla, minus its 

 skeleton. The anambulacral plating may be very extensive, forming 

 a complete pavement over the ventral surface of the disk as in many 

 Pentacrini ; and the ambulacra are not wide and open as is usual in 

 most Comatulce, but almost entirely closed by the approximation of 

 the marginal leaflets at their sides, so that the food-grooves radiating 

 from the mouth are converted into tunnels. In Loven' s specimen the 

 mouth was central but almost concealed, and several similar ones 

 were obtained by the " Challenger r ' at Cape York, together with one 

 still retained in its calyx and similar in every respect to an ordinary 

 Anteclon. This last shows that it is only on the disk that the ambulacra 

 are partially closed, for they are quite open and of the usual character 

 on the arms. 



Species of Actinometra may also exhibit this condition of more or 

 less completely closed ambulacra on the disk. One of the most 

 abundant Comatulce at Cape York is a large Actinometra, the disk of 

 which corresponds exactly to Loven's description of Hyponome, except 

 in the eccentric position of the mouth. Since learning the true nature 

 of Hyponome from Sir Wyville Thomson, I have looked out for a 

 similar condition in other Comatulce, and have found that it is not 

 uncommon though rarely so marked as in the Cape York species. 



Two species of Anteclon, dredged by the " Challenger" at Station 

 214, have disks, which } if separated from their dorsal skeleton, would 

 be very perfect Hyponomes. In each species the whole of the ventral 

 perisome is covered with an extensive anambulacral plating, and the 

 marginal leaflets at the edges of the grooves of both disk and arms 

 also contain distinct plates. In most Comatuhe there are no plates in 

 the marginal leaflets, or at most, a few calcareous spicules, irregularly 

 disposed. In these two species, however, there are definite plates 

 which are comparatively small as in Pentacrinus, and do not attain to 



