Vol. 56.] FORMATION" ANJ) ITS GRAPTOLITE-FATJNA. 



467 



Eig. 15. — M. varians, 

 sp. nov. (x5). 



British Localities. — Ludlow district (Elton-Evenhay Lano, 

 Elton Lane, and Stormer Hall) ; Abberlej Hills ? 



Horizon. — Zone of Monoyraptus Nilssoni. 



Associates. — M. chimcera var. Salweyi, M. serra, M. varians 

 var. pumilus, and M. Nilssoni. 



MoNOGEAPTUS VARIANS, sp. n0V. (PL XXV, figS. 14 A & 14 B.) 



Polypary rarely exceeding 25-4 mm. (1 inch) in length, and 

 generally only about 19 mm. (*75 inch) long. Straight distally, but 

 with a distinct incurve at the proximal end. Width at proximal 

 end = about '76 mm. (-05 inch), the maximum width usually attained 

 at the distal end being L77 mm. (*07 inch). Width increasing 

 throughout the polypary, but most marked at the proximal end, 

 where the rate of increase is approximately *084 mm. (-003 inch) 

 for each theca. Distal prolongation of the virgula very charac- 

 teristic, being often as much as 12*7 mm. (-5 inch). 



Proximal Extremity. — Sicula 1*77 mm. (-07 inch) long, and 

 about *32 mm. (-012 inch) wide, hence 

 5^ times as long as wide. Its relation 

 to the first theca is the same as in M. 

 colonus. Apex of sicula slightly above 

 the aperture of the second theca. 



Theca?. — Thirty-two to twenty-six 

 in the inch (thirteen to ten in 1 cm.), 

 inclined to the axis at an angle of 30° 

 to 35° (in exact profile). Proximal 

 three thecEe with distinct apertural 

 spines, the remainder having a concave 

 aperture of the usual type. Proximal 

 thecae about twice as long as wide, the 

 adult thecae from 3| to 4 times. Free 

 for nearly three-quarters of their 

 length, the outer and lower free wall 

 being convex just below the aperture, 

 and then becoming distinctly concave 

 close to the aperture of the theca 

 below, thus presenting the appearance 

 of a marked excavation at that point. 

 When preserved in true profile, this 

 is not so conspicuous. The length of 

 an adult theca is 2'2 mm. ("08 inch). 



Localities. — Long Mountain 

 (Lower W'innington, Dingle Mill, etc.) ; 

 Montgomery Road ; Ludlow district 

 (Stormer Hall, etc.). 

 Horizon. — Zone of M. Nilssoni. 



Associates. — M. Nilssoni, M. dubius, M. uncinatus var . orbatus , 

 Retiolites spinosus, M. crinitus, and M. chimcera var. Saliveyi. 

 Affinities, etc. — At first sight this form appears to be closely 



n 







a & b — Proximal extremity, 

 showing the sicula ; from 

 the road above Garbett's 

 Hall. 



c= Distal thecae of the reverse 

 side of fig. 14 a in PI. 

 XXV. 



