OF ARTS AND SCIENCES. 411 



base becoming inflexed ; an urceolate outer exciple bordering with 

 an obtuse, smooth, or at length radiate-striate margin an impressed, 

 rounded, and pore-hive aperture. Disk not visible until exposed by the 

 knife, a little concave, pale within, more or less white-veiled ; a section 

 showing it to be included within a brown line, which extends upwards 

 into the exterior exciple. Spores at length broad-oblong, colorless, 

 from diblastish becoming regularly tetrablastish ; the sporoblasts, or at 

 least the middle ones, flattened ; from once and a half to twice and a 

 half longer than wide. Pai-aphyses filiform. A neat and distinct 

 Theloti'ema, which I cannot refer to any published species. T. urceolare 

 Ach. Syn. p. 115, as described, appears in some respects similar, but 

 the spores, according to Nylander, (Lich. exot. in Ann. Sci. 4, 11, 

 p. 222,) are brown and murally divided. 



Thelotrema actinotum, sp. nov. : thallo effuso membranaceo 

 glaucescente mox granulate, granulis minutis demum congestis Ccesio- 

 nigricantibus ; apotheciis majusculis scutelliformibus sessilibus subplanis, 

 excipulo exteriori margine crassiusculo obtuso albicante discum nigri- 

 cantem velo margini concoloi'e radiatim perforate vestitum cingente. 

 Sporfe parvje, incolores ex ellipsoideo subfusiformes, tetrablast^e, diam. 

 2^ - 4-plo longiores. On trunks, incrusting small ferns and mosses, 

 Monte Verde, island of Cuba, Mr. Wright. Thallus very thin, glau- 

 cescent, at length besprinkled with minute granules, which become 

 heaped, and grayish-black. Apothecia large, often a line in diameter ; 

 scutelliform, adnate, flat ; a rather thick and entire, white, outer mar- 

 gin bordering a thin, pale disk, which blackens above, and is veiled 

 by processes from the inside of the margin, which meet in the centre, 

 from which they appear to radiate. Spores small, colorless, tetra- 

 blastish. Paraphyses filiform, distinct. In this species, which is strik- 

 ingly Lecanorine in aspect, the veil, as in the last species, appears to be 

 made up of processes from the inner side of the outer exciple, and, as in 

 that, to indicate the otherwise evident tendency of the Thelotremaceous 

 apothecium to develop, atypically, into a composite one ; sometimes 

 curiously suggestive of that of Pertusaria. 



Thelotrema schizostomum, sp. nov. : thallo tenui laevigato inte- 

 quabili e glauco-viridulo lutescente, hypothallo nigricante sublimitato ; 

 apotheciis mediocribus innato-prominulis demum dilatatis e rotundato 

 diflx)rmibus, excipulo exteriori erectiusculo mox fisso recurvo discum 

 planum pallidum albo-pruinosum vel velatum cingente. Sporae suboc- 

 tona3, incolores, fusiformes, 4 - lO-blastte, diam. 4 - 8-plo longiores. On 



