MONOGRAPTUS. 



503 



ing to the 



Genus Monograptus. 





















GROUP 



V. 











St. flagellaris. 



M. capillaceua. 



M. retrojlexus. 



31. dextrorsus. 



3[. remotus. 



M, Barrandei. 



M. inockemis. 



M. CUngani. 



M. millepeda. 





Small coni- 

 cal spiral 



Flexed, in- 

 curved dis- 

 tally and 

 recurved 

 proximally 



Slender, 

 arcviate, 

 reflexed 

 proximal 

 portion 



Slender, 



arcuate or 



flexed 



Slender, 

 arcuate 



Long, very 

 slender, 

 arcuate 



Straight or 

 with very 



slight 

 curvature 



Long, arcuate, 



broadly re- 

 curved proxi- 

 mally 



Long, arcuate, 

 abruptly 

 involute 

 jn-oximal 

 portion 





1 mm. 



1 mm. 



•75 mm. 



1 mm. 



'6 mm. 



•5 mm. 



1-5 mm. 



I'o mm. 



1'5 mm. 





— 



1 mm. 



— 



1-4 mm. 



— 



— 



— 



12 mm. 



1 mm. 





12 



8—10 



10 



7—8 



3—4 



7-8 



7 



12—7 



14—10 





Slight 



Insignificant 



Insignificant 



Slight 



Increasingly 

 remote 



Insignificant 



Nil 



Slight 



— 





7 

 To 



i 



1 1 



a 3 



Twisted lobe 



— 



3 

 4 



2 

 3 



\-% 



f 





— 



Small 



Very small 



— 



Very small 



— 



1 

 a 



i-i 



i 





GROUP VI.— B (UNIFORM). 





M. profeitg. 



31. 



delicahilus. 



3f. invohctus. 



31. ciyculai'i». 



31. communis. 





31. fimbriafus. 





3J. planui. 



31. inter- 

 medins. 



M. cf. 

 eloiigatus. 















y&v.rosfrafus. 





var. similis 











Helicoid 



spiral, 



slender 



proximally, 



but widening 



rapidly 



Slender, 



irregular 



spiral 



Irregular, 



involute, 



slender 



spiral 



Slender, 



convolute, 



coiled into 



plane 



spiral 



Arcuate or 



straight, 



with sharply 



recurved 



proximal 



portion 



Broader 



Small, 

 broadly cir- 

 cinate, with 

 circinate 

 proximal 

 portion 



Circinate 

 portion 

 shorter 



Small, 

 arcuate, 

 with re- 

 curved 

 proximal 

 portion 



Long, 

 arcuate, 

 with stiffly 

 recurved 

 proximal 

 portion 



Long, 



irregularly 



flexed, 



arcuate 





16 mm. 



1 mm. 



1 mm. 



1 mm. 



1'4 mm. 



— 



I'S mm. 



— 



1 mm. 



1 mm. 



1 mm. 





— 



— 





— 



1'2 mm. 



— 



1 mm. 



■7 mm. 



— 



— 



— 





7—10 



10 



8 



8 



8 



Longer 



12—9 



18—14 



14—12 



8—10 



8—9 





i 



Like M. 



convolittus, 



but 



smaller 



Like M. 

 covimunis 



Like that 



of M. 

 commxinis 



i 



— 



Mere 

 fraction 







Consider- 

 able 

 fraction 



Insignifi- 

 cant 



1 





Variable 



— 



— 



— 



tV 



— 



Nearly com- 

 plete 



— 



Nearly 

 complete 



1 



I 

 3 



GO 



