THE CRINOIDEA 



193 



muscular articulation, and to IBr 2 by incomplete syzygy. Arms hetero- 



tomous ; each gives off 5 unbranching rami nearly as stout as the main 



stem, 2 to right and 3 



to left, or vice versa; the 



first main -axil is the 



10th or llth brachial, 



succeeding branches are 



at much greater inter- 



vals ; pinnules occur 



below lAx, on IBr 4> 6 g 



or IBr 4> 6> 7 9 those 



being as a rule epizy- 



gals. There are dis- 



tinct Amb and adAmb, 



both in arms and teg- 



men. The proximal 



region of the arms is 



fixed by the tegmen, 



so that the grooves of 



the proximal pinnules 



rise from the tegminal 



food - groove (Fig. 



XXIV.). Small iBr 



, -i -11 c -,->-,-> legmen or uaiamocrinus Dlomedac, witli the arms and pin- 



rest on snouiaers OI KK nu ies cut off down to the level at which they become fixed in 



' 



/Br_. 



P 2 



P3 



FIG. CXIV. 

 Tegmeu of Ccdamocrinus Diomedat, with the arms and 



ambulacrals or covering-plates'; ^4s, anus 



A i j nx, axial canal of arm ; cc, coeliac canal of arm ; fy, food-groove 



lorate lAmb, and these of anterior arm where it joins the tegminal food-groove ; IBr, 



and merge into imper- 

 " 



primibrach ; iAmb, iuterambulacrals, both perforate and im- 

 perforate ; pi, first or proximal pinnule ; p2, second ; p3, third 

 iAmb : 5 imperforate. pinnule ; stc, subtentacular canal of anterior arm ; w.p, water- 



plates at the interraclial pore- - < After A s assiz >- x 



angles of the peristorne are taken by Agassiz for (Fig. CXIV.). 

 Stem long, smooth ; root encrusting (Fig. CXIII. 2). FAMILY 2. 

 BOURGUETICRINIDAE. Pinnata in which the patina consists of 5 BB 



a.c 



FIG. CXV. 



Bourgueticrinns. 1, B. aeqiuilis (from Brit. Mus. E6705). 2, ventral view of same (from 

 E6706). 3, joint-surface of proximale (P), by which it articulates with adjoining columnal (C). 

 4, vertical median section of B. ellipticus (after d'Orbigny). All x 4 diam. 



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