380 xxiv. chroococcace.e (West). [Gloiocapsa 
The integuments were very fine, and occasionally of a yellowish 
colour. 
Ambaca. — Alga rupestris, latas plagas rupium cavernaa Puri- 
Cacarambola internarum colore viridissimo tingens : Oct. 18f>G. 
Xo. 154. 
2. G. punctata Nag. Gatt, einz. Alg. 51, b. i. f, f. 6 (1849); 
W. et G. S. West in Journ. Bot. 1897, p. 302. 
GOLUNGO Alto. — Cum G. rupestri, ad saxa mollia juxta cataractam 
riv. Coango prope Sange, pone domicil. Domini Velho Castro : Sept. 
L856. Xo. 134. 
3, G. rupestris Kiitz. Tab. Phyc. i. (1845-9), 17-18, t. 22, f. ii. ; 
Rabenh. Flor. Europ. Alg. ii. ,47 ; W. et G. S. West, I.e. 
Goltjngo Alto.- -Cum G. punctata, ad saxa mollia juxta cataractam 
riv. Coango prope Sange ; Sept. 1856. Xo. 134. Eodem loc. prone 
Mata do Velho Castro ; Sept. 1856. Xo. 278. 
5. CHROOCOCCUS Nag, (1849). 
1. C. minutus Nag. Gatt. einz. Alg. 46 (1849); W. el G. S. 
West, I.e. 
Protococcus minutus Kiitz. Phyc. Gener. 168 (1843). 
Huilla. — In uliginosis editioribus prope Humpata, Empalanca et 
Lopollo ; May 1860. Xo. 15. 
2. C. turgidus Nag., I.e. (1849) ; W. et G. S. West, I.e. 
Protococcus turgidus Kiitz. Tab. Phyc. i. (1845-9), 5, t. 6. 
Huilla. — In paludibus exsiccandis : April i860. Xo. 176- 
3. C. pallidus Nag., I.e., t. i. a, fig. 2 (1849); W. et G. S. 
West, l.C. 
Huilla. — In uliginosis editioribus prope Humpata, Empalanca et 
Lopollo: May 1860. Xo. 15. 
4. C. schizodermaticus West in Journ. R. M. S. Dec. 1892, 742, 
t, x. fig. 61-63 ; in Journ. Linn. Soc. xxx. 275, t. xvi. f. 19 (1894). 
Var. badio-purpureus W. et G. S. West in Journ. Bot. 1897, 
p. 302. 
GOLUNGO Alto. — Inter Sei/tomma insigne, ad rupes madidas in 
umbrosis juxta rivum Coango inter Sange et Undelle : May 1856. 
Xo. 5. Ad rupes juxta riv. Coango (X-della), crustam viscoso-carti- 
lagineam fusco-badiam formans, Collematis thallum fingens ; June 
1856. Xos. 139 and 140. 
Welwitsch contributed to the Journal of Travel and Natural 
History, vol. i. pp. 22-36 (1868), a paper entitled "The Pedras 
Negras of Pungo Andongo in Angola," in which he shows that the 
prolific growth of a subaerial alga is the cause of one of the main 
features of the cotmtry, as it gives such a peculiar aspect to the 
mountains that they are known as the " black rocks/' He writes 
that it is " probably a non-described species of the prolific genus 
Scyton&ma, which in that situation during the rainy season 
generates and multiplies so rapidly that the upper portions of the 
