'38 



SYSTEMATIC HISTORY OF THE INFUSORIA . 



smooth, iu f. v. prolonged at each lateral 

 extrejuity into a mammillate projection, 

 which is terminated by a subulate, acute, 

 straight awn, the awns divergent ; e. v. 

 with three or four angles ; angles inflated, 

 mammillate, terminated by an awn, sides 

 deeply concave at the centre. L. 1-657 "j 

 B. 1-1064". G.B., F., U.S.A. 



2 t Segments smooth, angles in e. v. not 



inflated^ sides straight, or nearly so. 



S. O'Mearii (Archer). — Segments 

 smooth, in f. v. somewhat cuneiform, 

 gradually tvidening upivards, outer margin 

 truncate, a's\-iis acute, divergent j e. v. with 

 three or four acute angles terminated by 

 an awn, sides straight. Sporangium orbi- 

 cular, spinous ; spines subulate, acute, 

 ultimately somewhat inflated at the base. 

 a, e. V. with fom* angles, awns compa- 

 ratively short. L. 1-1866"; B. 1-2500". 

 /3, e. V. with three angles, awns longer. 

 L. 1-1750" ; B. 1-2300". I. 



S. minus (Kg.). — Segments smooth, 

 very minute, in e. v. with^re angles, each 

 terminated by a very minute acute spine ; 

 sides sti-aight. G. 



S. glahrum (Kg.)- — Segments smooth, 

 in f. V. cuneate, ends concave or straight, 

 spines slender, mucro-like; e. v. with three 

 mucronate angles, sides concave. I., G. 



3t Segments rough with minute 

 granules. 



S. lunatum (Ralfs). — Segments in f. y. 

 externally lunate, the inner margins con- 

 vex, the outer somewhat tnmcate, and 

 rough with minute granules; spines subu- 

 late, acute, curved, obliquely directed out- 

 wards and upwards ; e. v. with three in- 

 flated romided angles, terminated by a 

 spine, sides concave at the centre. L. 

 1-856"; B. 1-686". G.B. 



S. granulosum (Ralfs). — Segments in 

 f. v. broadly fusiform, granulate, lateral 

 extremities pointed, mucronate] e. v. with 

 three subacute mucronate angles, sides 

 conyex. = Desinidium granulosum (Ehr.), 

 " S. acutmu (Breb.). F., G. 



2 * Segments hi f. v. with each of the op- 

 posite latei'al extremities furnished with 

 a mucro or a simple subulate s^nne, 

 which in end vieiv tei'minates the angles, 

 and is accompanied by others interme- 

 diate of a similar character. 



S. pungem (Br^b.). — Segments in f. y. 

 externally lunate, the inner margin 

 curved, the outer tnmcate, smooth ; the 

 lateral marginal spines subulate, curved, 

 directed obliquely outwards and upwards, 



with six other spines on the outer margin, 

 also directed outwards ; e. v. with three 

 angles, each terminated by a spine, and 

 with two others at its base on the upper 

 surface, and divergent at opposite sides, 

 sides nearly straight or slightly convex. 

 G.B., F., U.S.A. 



S. cristatum (Nag. sp.). — Segments in 

 f. V. broadly elliptic, inner margin some- 

 what more tm-gid than the outer, sub- 

 mammillate at each side, terminated by a 

 mucro or short sjnne, and possessing on the 

 outer margin a fete others directed towards 

 the angles: e.v. with three subacute mu- 

 cronate angles ; sides convex, with an in- 

 wardly curved, submargmal, single series 

 of short mucro-like spines directed to- 

 wards the angles, sometimes wanting 

 near the middle. L. 1-540" ; B. 1-543". 

 = Phycastrum (Pachy actinium) cristatum 

 (Nag.), Staurastrum nitidum (Ai'cher). 

 I.,G. 



3 * Segments with each of the opposite 



lateral extremities furnished with a bifid 



or forked spine, its subdivisions subulate, 



acute, in e. v. terminating the angles, 



and appearing as a mucro-like spine, 



with or without intermediate sjjines. 



S. Avicula (Breb.). — Segments in f. v. 



triangular or cimeate, ends truncate, 



smooth, vdth a single forked spine on 



each side ; e. v. with three inflated angles, 



the bifid spine appearing as a mucro, sides 



concave. L. 1-967"; B. 1-948". (in. 18, 



e.v. 19.) G.B., F. 



S. denticulatum (Nag. sp.). — Segments 

 in f. V. subelliptic, inner margin some- 

 what more turgid than the outer, both 

 undulate or toothed in a scolloped manner, 

 with a7i unequally forked or getninate 

 spine on each side, the iqjper longer than 

 the loiver, the lateral jjrojections having a 

 series of transvei'se rows of minute gra- 

 nules; e. V. with three subacute angles, 

 the spine appearing as a mucro, sides 

 slightly concave at the centre, the mar- 

 gin toothed as mentioned before. "L. 

 1-70"'; thickness 1-55'".''= Phycastrum 

 denticulatum (Nag.). G. 



S. armigerum (Breb.). — Segments in 

 f. V. turgid on inner margin, outer trun- 

 cate, smooth, with a forked spine on each 

 side, and a few simjjle or forked, sometimes 

 minute, spines disposed at equal ititervals 

 bettveen, on the outer margin ; e. v. with 

 three angles, the bifid spine appearing as 

 a mucro, and the intermediate spines 

 projecting on each side. Sporangium or- 

 bicular, spines numerous, elongate, sub- 

 linear, forked at the apex. = S. spinosum 

 (Ralfs). G.B., I., F. 



