1886.] MIOEOSCOPICAL JOURNAL. 127 



n. Ends truncate ; semi-cell triangular ; diameter -g^f^ in. (50;/.) or less, 



galeritum^ *]o. 

 n. '' semi-cell subsemicircular, smooth ; sinus deep, narrow, 



iiitidiihim, 62 ; pseitdonitiduhim, 62. 

 o. Sinus deep, narrow (/). 



0. Sinus deep, wide, almost linear ; cytioderm smooth . . seju7icttim, 62. 

 o. '' rounded or oval; semi-cells Innately curved; cytioderm 



punctate lunatum^ 65. 



p. Cell elliptical ; basal angles acute Bailey i\ 64. 



p. Cell suborbicular ; basal angles obtuse ; diameter g^^ to j-|^^ in. (60-100//), 



Ralfsii^ 69. 

 p. " " " diameter^V^to gig in. (30-38//), 



constricttun^ 58. 

 r. Cytioderm centrally somewhat granular ; nucleus i in each semi-cell, 



tumidtim^ 61. 

 r. " smooth or punctate ; cells small, bioculatjini^ 60 ; tinctHin^ 61. 



s. Ends rounded ; semi-cells semi-orbicular ; crenee usually 9, 



u/idii latum, 6'j. 

 s. Ends truncate ; semi-cells pyramidal ; cells small . . notabile, 66. 

 s. " sides almost parallel ; diameter -^^ to -^j^^ in. (30-38/^.), 



crenatuni, 67. 

 s. " sides converging ; diameter y^^-j^^ in. (20/-/-), 



NcBgelianuvi, 67. 

 /. Semi-cell quadrate, smooth, angles rounded ; end retuse or convex, 



quadratiim, 59. 

 t. " pyramidal or subquadrate ; end undulate . Uolfuiense, 6^. 



t. " " end truncate ; diameter ^i^- to ^i^^ in. (32-36//), 



integrum, 68. 



t. " " " diameter yoVo to T2V0 i"- (20-24.'''-) 5 



Hammer i, 79* 

 t. Semi-cell pyramidal, punctate, base flat, angles rounded, 



ansatn7ii, 68 ; Nymainiiainim. 79. 



u. Diameter ^\-^ to ygVo' "^- (20-30//.) punctnlatum, 74. 



u. Diameter y^Vo to ysVt ""*• (14-16//) Icevc, 62. 



V. Cell twice as long as wide, rectangular ; sinus linear, not widened, 



sinj(osii7n, 65. 

 V. Cell less than twice as long as wide ; semi-cell pyramidal, venustum, 68. 

 V. " "• " *■' semi-cell subquadrate, small. 



Men egh in ii, 65 . 

 ■w. Sinus narrow, not widened outwardly ; cell elliptical, end convex, 



variolatum, 63 ; exiguutn, 66. 

 w. vSinus widened and rounded inwardly, narrowing outwardly, cell wider 



than long obsoletuni, 64- 



XV. vSinus widened outwardly ; semi-cell oval, base and end convex, 



coutractiivi, 63. 

 w. '•' " " " base and end flattened, 



depresstcm, 64. 

 w. Sinus widened outwardly ; semi-cell quadrate . . . Mcneghinii, 65. 

 w. " *•' semi-cell subsemicircular; diameter ^^\-^ to 



3^75 in. (75-100//) pachydermum,, 70. 



X. Margins crenate or granulate ( r) • 



X. Margins not crenate nor granulate {bb^ . 



y. Central verrucas none or scattered on each semi-cell {z) . 



y. "•' more or less clustered on each semi-cell {aa). 



