THE CRINOIDEA 



189 



are few and have the proximal larger than the rest ; with isotomous 

 arms which may abut but do not interlock ; anals form a well-defined 

 vertical series. Genera Gnorimocrinus, W. & Sp. (1879, em. Bather, 

 1899), Silurian, Gotland ; arms distinct, with 0-4 small iBr, and 

 sometimes a few illBr ; post. B reaches up to top of patina, between 

 it and r. post. R is a RA, supporting the greater part of cc, which bears 

 a vertical series of 1 or 2 rows. Anisocrinus Angelin (1878), Silurian, 

 Gotland, has abutting but not interlocking arms, a very large proximal 

 iBr, with small triangular piece above ; x differs from iBr only in 

 resting on truncate edge of large post. B ; no RA. Taxocrinus, Phillips 

 in Morris (1843; synn. Isocrinus, Phill. non v. Meyer; Cladocriniis, 

 Austin non Agass. ; Euryalecrinus, Aust. ; Forbesiocrinus, de Kon. non W. 

 & Sp.), Silurian to Carboniferous, Europe and N. America, has arms 

 more distinct, with few or no iBr, and occasional small illBr and illlBr ; 

 anals form a vertical series resting on truncated post. B, and seem to 



Fia. CX. 



Diagrams of the arm-branching in Taxocrinidae and Dactylocrinidae. 1 2 3 



1, Taxocrinus tuberculutus ; 2, Litkocrinus ; 3, Ccdpiocrinus ; 4, Dactylo- /\ 



criniis; 5, Synerwrinus ; 6, Onychocrinus exsculptus. These do not form / 4 



a continuous evolutionary series, but their relationship may be indicated / | 



thus 6' 5 



I 



have supported a small free tube (Figs. CX. 1, and XXXVII.). Homalo- 

 crinus, Ang. (1878), Silurian, Gotland, has very small BB. abutting arms r 

 large proximal iBr, followed by 1 or 2 in vertical series, occasionally 2 

 illBr, anals as iBr but resting on post. B ; except for the isotomy of its 

 arms, this genus closely resembles Ccdpiocrinus. FAMILY 4. DACTYLO- 

 CRINIDAE. Impinnata with iBr either few or numerous ; with hetero- 

 tomous arms, the rami bearing ramules ; with anals in vertical series. 

 Genera Calpiocrinus, Ang. (1878), Silurian, Gotland and England, has 

 minute often obsolete IBB, but fairly large BB ; iBr few and variable, 

 illBr occasionally present ; anals 3-5, x resting on the small post. B ; the 

 IIBr rami bear unbranched ramules on their inner sides, the proximal 

 ramule much larger than the rest (Fig. CX. 3). Lithocrinus, W. & Sp. 

 (1879, emend. Bather, 1899 ; syn. Forbcsiocrinus, Ang. non. de Kon.), 

 Silurian, Gotland, differs from Calpiocrinus in larger size of BB, greater 

 number of iBr, branching of ramules ; the latter characters make the 

 arms less apposed to one another (Fig. CX. 2). Dactylocrinus, Quenstedt 



