146 THE REV. W. А. LEIGHTON ON NEW BRITISH LICHENS. 
margin; hypotheciwm colourless, or only very slightly yellowish at the very base; 
paraphyses indistinct, conglutinate, apices brown; spores 8, colourless, oblong, 
1-septate, somewhat constricted in the middle. 
On maritime rocks, Boulay Bay, Jersey, Mr. Larbalestier (May 1872). 
Spores “019 mm. long, "0085 mm. broad. No spermogonia detected. Medulla 1—. 
Gelatina hymenia I—. 
This very interesting lichen was sent to me for determination by Mr. Larbalestier 
immediately on its discovery in 1872; and I at once saw that it was a new and distinct 
species, and named it L. subdiluta, from the general external resemblance of the 
apothecia to those of L. diluta (Pers.). This name I communicated to Mr. Larbalestier 
(in litt.) in 1872 ; and he subsequently deposited specimens with that name in Herb. Brit. 
Mus. and in several private herbaria. Тһе lichen was subsequently shown by Mr. Lar- 
balestier to Dr. Nylander, who, as Mr. Larbalestier informed me (in litt.), thought it 
“а seaside anomalous state of L. prosechoides, Nyl., and not worth distinguishing," 
which of course it is not. Sincethen Dr. Nylander has changed his opinion, and now 
describes it as a “ species notabilis" in the * Flora,’ 1875, р. 442, under the name of 
Lecanora jejuna, Nyl. My name L. subdiluta, Leight., claims priority. 
LECIDEA ADVENULA, Leight. "Thallus obsolete; apothecia nigro-fuscous, minute, round, 
plane or subconvex, with a thin margin soon obliterated, brownish within; para- 
physes indistinct, conglutinate, apices large, nigro-fuscous ; hypothecium thickish, 
nigro-fuscous ; spores 8, nigro-fuscous, oblong, 1-septate. 
Parasitic on Pertusaria sulphurea (К. yellow, С orange-red). 
On rocks, Llanbedrog, near Pwllheli, North Wales, 1874. Very rare. 
A very singular lichen, not scattered uniformly over the matrix thallus, but occurring 
only on blackened patches formed by some conglomerate spherical brown alga at 
intervals over the thallus. Gelatina hymenia I—. Spores "024 mm. long, 018 mm. 
broad. 
MELASPILEA VERMIFERA, Leight. Thallus obsolete; apothecia black, very minute, irre- 
gularly angulari-oblong, imbedded in the cortical layer, when dry plane and sur- 
rounded by a minute upraised jagged margin of the cortical layer, when wet plano- 
convex, the margin obliterated; hymenium pale; paraphyses very delicate and 
slender, apices pale; asci lineari-obovate ; spores innumerable, colourless, arranged 
spirally in the ascus, cylindrico-fusiform, pointed and arcuate at each end, vermiform: 
1-septate. 
Parasitic on the thallus and apothecia of Variolaria discoidea, Т. & B. (Pertusaria 
globulifera, Turn.). 
On oaks, Trefriw, North Wales, 1874. Rare. Gelatina hymenia I—. Spores "022 
mm. long, "002 mm. broad. 
ARTHONIA PUNCTILLIFORMIS, Leight. Thallus a mere film; ardelle nigro-fuscous, exces 
sively minute, not larger than a pin’s point, irregularly roundish, convex, scattered, 
