46 REVIEWS — CANADIAN ORGANIC REMAINS. 



eight to eleven irregular rows ; the mouth is provided with a valvular 

 apparatus, and there are free arms. The genus Amygdalocystites 

 possesses the same plate-formula as- Comarocystites, and the mouth 

 is also furnished with a valvular apparatus ; but, in addition to other 

 distinguishing characters, the arms are recumbent, and composed of 

 a double in place of a single series of joints. Three species are 

 enumerated. One of these, however, may belong to a distinct 

 genus, and the other two may perhaps be united. They comprise : 

 A.florealis, A, temdstriatus (?), and A. radiatus. In both Comaro- 

 cystites and Amygdalocystites the plates are without pores, at least 

 ©n the unworn external surface. The genus Malocystites has like- 

 wise an indefinite number of non-poriferous plates.* The arms are 

 recumbent, and the mouth is nearly at the apex of the cup. Two 

 species are described : M. MurcMsoni, with eight long and wiuding 

 arms, and M. Barrandi, with two short arms. In the genus named 

 Palaeocystites, the plates are numerous and also poriferous, or 

 rather crypto -poriferous, as the pores do not extend directly to the 

 outer surface, but communicate with the interior through the sutures, 

 on the edges of which they open. Nothing is known respecting the 

 arms, orifices, and stem. Three species are enumerated : P. tenui- 

 radiatus,-\ P. Bawsoni, and P. CA«p»zflm, but their specific characters 

 are necessarily somewhat obscure. Finally, in the genus Ateleocys- 

 tites, a single species, A. Ruxleyi, is mentioned. The calyx in this 

 form appears to have, as in Pleurocystites, a dorsal side made up of 

 comparatively few plates, with numerous small plates on the ventral 

 side. In other respects, however, the genus is a very peculiar one, 

 and perhaps referable to a distinct group. 



In his enumeration of our Canadian star-fishes, besides two species 

 of McCoy's, or Salter's, Palasterina, Mr. Billings describes several 

 new genera : Stenaster, Petraster, and Tseniaster, amongst ordinary 

 star-fishes, and Edrioaster belonging to the abnormal sessile group. 

 The latter genus was named Cyclaster in Mr. Billings' Eeport for 

 1856 ; but it was subsequently found that the same generic name 

 had been applied in France, just previously, to a new genus of 



• As subsequently shown, however, by Mr. Billings, the pores in Comaroeys^ites appear 

 to open out on the sides of the plates at the sutures, as in the genus Palseocystites. May 

 not this be the case, also, with regard to Cryptocrinus (Von Buch), and the other so-called 

 non-poriferous types ? E. J. C. 



t This is the Aetinocrinus tenuiradiatus of Hall. The other species appertaining to the 

 dififerent genera enumerated in the text, belong entirely to Mr. Bilhngs. 



