42 CALAMOCRINUS DIOMED^. 



resting upon the solid interradials. The interr.idial plates of this speci- 

 men differ as regards their shape and arrangement in each interradium. 

 He could not find any trace of the furrows leading from the arms to the 

 buccal orifice, nor could he satisfy himself it was placed at the extremity 

 of this sac. He speaks, however, of a multitude of microscopic pieces to 

 be seen piled opposite one of the rays, and I am inclined to consider 

 the conical sac of de Loriol the anal proboscis, and to think that in a 

 better preserved specimen we may be able to trace the ambulacral farrows, 

 though they may be quite closed by just such movable covering plates as 

 he has observed. The ventral sac is even more mobile than the anal sac 

 of Calamocrinus, judging from the size of the plates covering it, and from 

 what de Loriol saj's of their thickness. In fact, all the interradial plates 

 he figures are comparatively smaller than those of Calamocrinus, and pass 

 earlier into genuine irregular perisomic plates. 



In the case of a specimen of Apiocrinus magnificus, de Loriol speaks 

 of the interradial plates as thin and flexible, forming a sort of swelling 

 (Plate III. Figs. 3, 3% 3''). In a Avell preserved calyx of Millericrinus Fleu- 

 riansianus (Plate III. Fig. 2") the walls of the cavity are deeply grooved, 

 the petaloid depressions for the reception of the chambered organ are large, 

 and the canals which limit them well defined. 



Wagner* discovered a specimen of Encrinus Wagneri with a well pre- 

 served vault extending to the upper articulation of the first radials. The 

 large conical vault is composed of cii'cular and elliptical larger and smaller 

 granules and plates. Tiio plates are well specialized, with a most distinct 

 suture. The larger plates were in close and solid connection, which, as 

 Wagner says, closely resembles the vault of Apiocrinus Roissyanus described 

 by de Loriol, having a considerable rigidity and perhaps a slight degree 

 of pliabilit}'. 



Buckland f gives an excellent figure of the " plated integument of the 

 abdominal cavity " of Pentacrinites biiareus. 



Von Koenen $ in the abstract of his larger memoir on Muschelkalk En- 

 crinites, speaks in Dadocrinus of remains of plates to be seen between the 

 spaces of adjoining arms of the second and third radials, which are to be 

 considered as perisomic. Dadocrinus and Encrinus seem according to him 



* Ueber Encrinus Wagneri Ben. aus dem unteren Mu.schelkalk von Jena. Richard Wagner, Zeitscli. 

 d. Deutschen Geol. Ges., 1887, XXXIX., p. 822. 



t The Bridgewater Treatises. Treati.se VI., Geology and Mineralogy, Vol. II. Plate 51, Fig. 2. 

 t Neues Jahi-huch f. Mineral., 1S87, II., p. SO. 



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