198 



THE CRINOIDEA 



water (Figs. CXXI. and XXXIV.). Cyathidium, Steenstrup (1846 ; syn. 



Micropocrimis, Michelin), Uppermost Cretaceous to Miocene, Denmark 



and Italy. FAMILY 9. EUDESICRINIDAE. 

 Pinnata (?) with patina of 5 RR, enclosing 

 funnel-shaped cavity open below, resting 

 on a solid mass which may represent 

 fused BB or a proximale. lax articulated 

 to IBr 1? and supporting 2 stout rami 

 which abut on adjoining rami. Axial 

 cords lie close to inner walls of RR. 

 Genera Eudesicrinus, de Loriol (1882) ; 

 and Cotylederma, Quenst. (1852 ; syn. 

 Cotylecrinus, E. Deslongch.), both Lias. 

 Jaekel would place these genera near 

 the Plicatocrinidae ; they are usually 

 referred to Eugeniacrinidae or Holo- 

 podidae. 



ORDER 3. Dicyclica Camerata 

 ( = CAMERATA, W. & Sp. pars). 



FIG. CXXI. 



Adult Holopus Eangi, from anterior. 

 (From A. Agassiz, after P. H. Carpenter.) 

 Enlarged by one-twelfth. 



Dicyclica in which all IBr and usually 



IIBr are incorporated in the dorsal cup by iBr, at first loosely, but 

 afterwards by close suture. IBB always the primitive 5. A plate 

 always between r. and 1. post. RR, resting on post. B, and followed by 

 others leading up to the anus. Mouth and ambulacra subtegminal. Arms 

 pinnulate. 



FAMILY 1. RETEOCRINIDAE. Dicyclica Camerata with RR and Br sepa- 

 rated by supplementary plates irregular in size, shape, and arrangement, and 

 forming depressed interradial areas, the posterior of which is divided by a 

 single vertical series of prominent plates leading from post.B to the eccentric 

 anus. Genus Reteocrinus, Billings (1859 ; see W. & Sp., 1897), Ordo- 

 vician, N. America (Fig. CXXII.) ; 2-3 IBr ; about 6 IIBr, of which the 

 pinnules, borne from IIBr 2 onwards, are also fixed in the interradial areas ; 

 the pinnule borne by IIBr 2 is in some species represented by a ramus, 

 partly fixed ; the rami may branch again after becoming free, and are 

 uniserial or slightly in zigzag ; tegmeu a low dome of minute irregular 

 plates; stem pentagonal. FAMILY 2. DIMEROCRINTDAE. Dicyclica Camerata 

 with RR in contact except at posterior side, with 2 IBr and a varying 

 number of IIBr, separated by a large proximal iBr, which rests on 

 shoulders of RR and supports 2 plates, usually followed by smaller 

 ones merging into iAmb ; post. IR wider, and its proximal plate (anal) 

 supports 3 plates followed by others, and leading up to anus, which 

 has no tube ; illBr usually present. Genera Ptychocrimis, W. & Sp. 

 (1885, em. 1 897), Ordovician, N. America ; arms fork twice, are slender and 

 uniserial as in Reteocrinus. Orthocrinus, Jaekel (1895), Devonian, Germany ; 

 arms fork once, are free from lax, stout and uniserial. Dimerocrinus, 

 Phillips (1836 ; synn. Glyptaster and Thysanocrinus, Hall em. W. & Sp., 



