l62 



THE CRINOIDEA 



Angelin (1878 ; [?] syn. Harmocrinus, Ang.), Ordovician, N". America, 

 and Silurian, Gotland (Fig. LXXV. 1, 2); 5 BB, uniserial arms, anals in 



FIG. LXXV. 



Patelliocrinidae. 1 and 2, Stelidiocrinus capitulum. 1, calyx from posterior ; 2, oral surface ; 

 3, Patelliocrinus pachydactylus. (All after Angelin, about nat. size.) 



post. IR, large orals. Macrostylocrinus, Hall (1852, W. & Sp., 1897), Silu- 

 rian, N. America ; 3 BB, biserial arms, anals in post. IE, small plates in 



teamen. Allocrinus, W. & Sp. (1889- 

 97), Silurian, N. America ; 3 BB, 

 uniserial arms, no anals in post. IE. 

 Patelliocrinus, Angelin (1878), Silurian, 

 Gotland (Fig. LXXV. 3) ; 3 BB, arms 

 zigzag or biserial, no anals. Briaro- 

 crinus, Angelin (1878), Silurian, Got- 

 land ; 3 BB, arms secondarily uni- 

 serial, i.e. IIBr are compound plates, 

 anals uncertain. Centriocrinus, Bather 

 (1899, nom. mut. pro " Centrocrinus," 

 W. & Sp., 1881, non Austin, 1843, 

 nee Worthen, 1890); BB fused, arms 

 unknown, no anals in post. IE. 

 FAMILY 4. CLONOCRINIDAE. Melo- 

 crinoidea with 4 BB ; in each half- 

 ray 1-2 IIBr, with varying number 

 of HIBr and even occasionally IVBr ; 

 free arms biserial, sometimes forking 

 as far as VIIBr ; iBr few and 

 definite ; illBr few, not always 

 present ; occasional illlBr ; no anals 

 in post. IE ; tegmen unknown ; stem 

 round or sub -pentagonal. Genera 

 Clonocrinus, Quenstedt (1876, non 

 Oehlert, 1879 ; syn. Corymbocrinus, 



poiydwtyius. i, from side An g-)> Silurian, England, Gotland, and 

 (from Brit. Mus. 40257) ; 2, vertical section N.America; base concave ; free arms 



isotomous from IIIBr to VIIBr ; iBr ina 

 single vertical row, the two proximal 

 large and definite. This genus leads towards Eucalyptocrinidae. Poly- 

 peltes,A.nge\in (1878), Silurian, Gotland, seems to have pinnules incorporated 



FIG. LXXVI. 



(from Brit. Mus. 

 usual. Nat. size. 



E6489). Lettering as 



