34 . PALEONTOLOGY. 



Poteriocrinits, extend into the carboniferous formations. Cu- 

 pressocrinus and some others are peculiarly Devonian; Platy- 

 crinus, common to Devonian and coal formations ; and many 

 genera (including the "nave Encrinite" — Actinocrinus, Gil- 

 bertsocrinus, and Woodocrimis), are proper to the carboniferous 

 limestone. The famous "lily Encrinite" (Encrinus entrocha, 

 fig. 6, 6) is characteristic of the middle trias, or " muschel- 

 kalk;" the "clove Encrinite" (Eugeniacrinus, fig. 7, 9) abounds 

 in the upper oolites of Germany; Apiocrinus, Millericrinus, 

 and several forms related to Comatula — e.g., Pterocoma and 

 Saccosoma — are also peculiarly oolitic. The "tortoise Encri- 

 nite" {Marsupites, fig. 6, 9), is found only in the chalk, along 

 with Bourgueticrinus (fig. 7, 10); and the bodies of Cornatulce, 

 which, when they have lost their arms and claspers, are 

 called "Glenotremites." (Fig. 7, 7, — upper surface with sockets 

 of the five arms; 8, — under surface, shewing articulations of 

 claspers, and the scar of the larval stem.) 



Order 2. — Cystoidea. 



This order was established by Yon Buch for a small group 

 of palaeozoic echinoderms formerly included with the Crinoidecz. 

 They have a globular body covered with close-fitting polygonal 

 plates, and supported, as a rule, on a simple jointed stem. 

 Opposite its attachment is the mouth, which is minute ; close to 

 it is a small opening like a generative pore ; and a little more 

 distant a larger orifice, covered by a pyramid of five or six little 

 valves. Some of the genera, like Pseudocrinus (fig. 6, 2), have 

 two or four tentaculiferous arms, bent down over the body and 

 lodged in grooves, to which they are anchylosed. Others, 

 like the Spliceronites (fig. 6, 1), have obscure indications of 

 tentacles situated close to the mouth. In Pseudocrinus and 

 some other genera two or three pairs of lamellated - organs, 

 called "pectinated rhombs," are placed on the contiguous 

 margins of certain body-plates. They are supposed not to 



