Vol. 56.] 



SHALES OF THE WELSH BOEDEELAND. 



411 



No further branching has been observed, though the main stipe 

 has been seen for 2 inches (50 mm.) after the branch is given off. 



In its proximal part this species is not unlike Cyrtograptus 

 Linnarssoni, Lapw., the branch being given off at the same distance 

 from the sicula, but the general form, absence of pronounced 

 curvature, direction of curvature of branch, and character of the 

 thecae in the adult parts easily distinguish it from that species. 

 In general form it is not unlike C. rigidus, Tullb., but differs from 

 that species in the character of the proximal end and the number 

 of thecae in the adult portions of the stipes. 



Characteristics : — 



(1) General form and presence of only one branch. 



(2) Number of thecse to the inch in the distal part of the main stipe 



and branch. 



(3) Abrupt widening and general width of the adult part, as compared with 



the proximal portions of the rhabdosoma. 



Horizon. — Zone of Cyrtograptus symmetricus. 

 Localities. — EuilthEoad; CoedMawr; Castle Crab. 



Table XI. — Distribution of Species in the Wenlock Shales. 



Names of Species. 



'1 



•si 



si 



■B-J 



N 



05 



Hi 



4s 



O £ 



SO 



O 



1 







O £ 



11 



O 



«H 

 © Co' 



O 



«4H S 



c *«. 



If 



C5 



*3 



U 







[C = very common ; c ■= com- 

 mon ; r = somewhat rare ; 

 R = very rare.] 



Cyrtograptus Murchisoni, Carr. . 



C 

 c 

 C 



c 



R 



C 

 C 



C 



r 



R 



c 

 C 

 r 



c 



c 

 C 



C 

 r 



c 



c 



C 

 r 



c 



c 

 R 



c 

 r 



c 



c 



c 



c 



c 



c 



r 

 r 



c 

 R 



C 



c 



C 

 C 

 r 



c 



C 

 c 



R 

 R 



C 



C 

 c 



C 



r 

 R 



C 

 C 



c 



C 



R 



c 



R 



R? 



c 

 R? 



C 









C. Carruthersi, Lapw.= 7 



Nilssoni (Barr.) ) ' 



Monograptus basilicus, Lapw. . . . 





M. Flemingii (Salt.) var. a 



» ' » var. (3 



>y „ var. y 



„ ,, var. 3 



M.fiexilis, sp. nov 



M. Hisingeri, Carr., var 



3f. irfonensis, sp. nov 



M. J&lceli, Perner 



M . priodon ( Bronn) 



31 . riccartonensis, Lapw 



31. retroflexus, Tullb. 



31. testis (Barr.) var. inomatus ) 

 nov. ) 



M. vomerinus (Nich.) var. a 



» . » var. fi 



M. colonus-Yike form 



Retiolites Geinitzianus. Barr. ... 



Retiolites sp 



Stomatograptus sp 









