FIIESH- WATER A LG OF Til E U NI TK D ST ATE S. H 



(i. mis CHROOCOCCUS, N^GELI. 



CcllulsD globose ovalcB vcl a pressione inutua plus minus angulosa;, solitaritc vcl in fumilias con- 

 Fuciuue, liber a; (a vesica matricali non involute) ; cytiodcriuate achromatico, bomogeneo, sajpe in niuco 

 plua minus lirmo couliucnte; cytioplasmate a.Tuginoso vcl pallide ca:ruleo-viridi, non rare luteolo Tel 

 auruiitiat-o, iiiterdutu purpurasccute.. Ocneratiouuni successivarum divisio altcruatim ad dircctioncs 



Syn. Frotococms, Ao. ct KTZ., Ac., ex parte. Pleurococcus, MENOH. 



Olobulinae ct Frotosjiharriee, TUKPIN, ex part. 



Cells globose, oval, or from mutual pressure more or less angular, solitary, or consociatcd in free 

 families (not involved in a maternal vesicle); Cytioderm achromatic, homogeneous, often confluent 

 int.' a more or le.ss linn mucus; cytioplasiu a?ruginous or palo bluish-green, not rarely yellowish or 

 orange, sometimes purplish. Successive generations arising by alternate division in three directions. 



C. refraclus, WOOD. 



('. eellulis in families solidas arete consociatis, plcrumquc subquadratis, sxpiiis triangularibu*, 

 rare angulosis; familiis sa-piua lobatis; cytiodcrmato tcnui, vix visibile, achroo; cytioplas- 

 mate subtiliter granulate, subfusco vel subluteo vel olivacco, yalde refrangente. 



Z>iam. Cell JB'OU" suW. rare in eellulis singulis nW; famil. -rA" ilo" 

 Syn. C. refractua, WOOD, Prodromus, Proc. Amcr. Philos. Soc., 1869, 122. 

 JIab. In rupibus irroratis grope Philadelphia. 



Cells closely associated together into solid families, mostly subqnadrate, very often triangular, 

 rarely multiangular ; families often lobcd ; cytioderm thin, scarcely perceptible, transparent ; 

 cytioplasm finely granular, brownish, olivaceous, or yellowish, highly refractive. 



/,'< marks. The color of this species varies from a marked almost fuscous brown 

 to a light yellowish-brown, the lighter tints being the most common. The cells 

 arc remarkable for their powerful refraction of the light, resembling often oil as 

 seen under the microscope, especially if they be the least out of the focus. They 

 arc MTV closely joined together to form the families, many of which are composed 

 only of four cells. Often, however, a large number of the cells arc fused together 

 into a large, irregular, more or less lobatc family, and these sometimes arc closely 

 joined together into great irregular masses. I have occasionally seen large single 

 cells with very thick coats, whose protoplasm was evidently undergoing division. 

 Arc such a sort of resting spore ? The color of the protoplasm varies. Perhaps the 

 more common hue is a sort of clay tint. Bluish-olive and a very faint yellowish- 

 brown are not rarely seen. The species grows abundantly on the wet rocks along 

 the Reading Railroad between Manayunk and the Flat Rock tunnel. 



Fig. 5, pi. 5, represents different forms of this species; those marked a, magnified 

 750 diameters ; J, 470 diameters ; c, 950 diameters. 



C. multicolorntiiH, WOOD. 



C. in strato mncoso inter algas varias sparsns ; eellulis singulis ct sphtericis, vcl 2-4 (rare 8) aut 

 angulis ant scmisphicricis ant abnormibns in familias oblongas eonsociatis ; cytioderraate crasso, 

 hyalino, hand laraelloso; tegumentis plerumque nullis, interdum snbnullis; cytioplasmate plc- 

 rumque homogeneo, interdum subtiliter granulato, vel lutco-viridc vcl ca;ruleo-viride vel lutco 

 Tel subnigro, vel brunnco, vel saturate aurantiaco, sa;pe ostro tincto. 



Dinm. Cell., sing, sine togm., *" cum teg. uVa"; cell, in famil. sing. *,," 

 Fara. long. i.V'-^S,"; Iat - o"-V- 



