MONOGRAPTUS. 



499 



Specific Clianicters of Forms helonqing to tlte Genus Monograptus. 





GROUP IV.- A. (UNIFORM). 



M. priodon. 



M. pandut. 



M. Marn. 



M. euUellu; 



M. riccarto- 

 nentii. 



M. 



Flemingii, 

















var. 

 primuf. 



var. 

 eompaetiiB. 



Character of polypary 



Very long, 

 straight 

 and rigid 



Approxi- 

 mately 



straight, 

 robust 



Long and 

 narrow, 

 approxi- 

 mately 

 straight 



Very short 

 incurved 

 proximal 

 extremity 



Slight 

 dorsal 

 flexure 



Straight 



or slightly 



flexed 



Straighter 

 and shorter 

 with more 



rapid 

 widening 



Very small 



and 



compact 



Maximum width 



3 mm. 



2-5 mm. 



1-8 mm. 



1 mm. 



1"5 mm. 



25 mm. 



— 



3 mm. 



Length of sicula 



1-5 mm. 



— 



1-2 mm. 



I'o mm. 



1'6 mm. 



1-6 mm. 



— 



— 



Characters of thecse : 

 1. No. in 10 mm. 



13—8 



9-10 



10 



20 



10—8 



14—9 



14-8 



16-18 



2. Overlap 



i-l 



f 



Slight 



Slight 



1 1 

 -3—3 



k 



— 



— 



3. Apertural region, 

 proportion to 

 width of polypary 



i 



\ 

 5 



+ h 



Like 

 M. discus 



i 



Abruptly 

 narrowing 



— 



— 



4. Proportion of 

 " hook " to the- 

 cal length 



i 



I 



+ k 





1 



2 



h 









GROUP IV.-A. {UNIFORM.) -continued. 



M. 





M. 









3/". ttndtt- 





M. 





uneinaiu 





irfonensis. 



M.fexiUs. 



if. acn». 



Jlf. distant. 



latus. 



M, scanicus. 



criniiui. 



var. 



var. 



















orhatui. 



mtcropoma. 

















Character of polypary 



Short, 



Straighter 



Very 



Long and 



Very 



Long and 



Long, 



Slender, 



Thread- 





robust 



and 



slender. 



flexed 



long 



slender. 



slender. 



very flexed. 



like, 





and 



narrower 



approxi- 



with 



and 



irregularly 



flexed, 



with con- 



irregia- 





somewhat 





mately 



reflexed 



flexed 



but con- 



with re- 



spicuous 



larly 





flexed 





straight 



proximal 

 portion 





spicuously 

 flexed 



curved 



l^roximal 



end 



proximal 



ventral 



curvature 



flexed 



Maximum width 



2 mm. 



1-3 mm. 



1 mm. 



2 mm. 



2 mm. 



1 mm. 



1 mm. 



1 mm. 



•4 mm. 



Length of sicula 



1-6 mm. 



— 



1 mm. 



2 mm. 



with long 



virgella 



— 



— 



I'l mm. 



1'5 mm. 



1"5 mm. 



Characters of thecse : 





















1. No. in 10 mm. 



12—9 



10—9 



8—9 



12—9 



8 



12—8 



10—8 



8—9 



5—7 



2. Overlap 



k 





Approxi- 

 mately 

 i 





Slight 



Like that 



ofproximal 



portion of 



M. Sedg- 



wicki 



l-h 



1 



Insigni- 

 ficant 



3. Apertural region. 



Like M. 



Beak less 



4 



Very like 



Very 



— 



% 



4 



Like M. 



proportion to 



Plemingii. 



con- 





M. 



slight 









scamcus. 



width of poly- 





spicuous 





Flemingii, 



retro- 









but 



pary 









hut 



shorter 



version 









more 

 slender 



4. Proportion of 



-h 







i 



-i 



— 



_ 



h 



4 







" hook " to the- 





















cal length 





















