380 XXIV. CHROOCOCCACE.E (West). \Gloeocapsa 



The integuments were very fine, and occasionally of a yellowish 

 colour. 



Ambaca. — Alga rupestris, latas plagas rupium cavernse Puri- 

 Cacarambola internarum colore viridissimo tingens : Oct. 1856. 

 No. 154. 



2. G. punctata Nag. Gatt. einz. Alg. 51, t. 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. 

 1856. No. 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. 



Goi.UNGO Alto. — Cum G.punctaki, ad saxa mollia juxta cataractam 

 riv. Coango prope Sange ; Sept. 1856. No. 134. Eodem loc. prope 

 Mata do Velho Castro ; Sept. 1856. No. 278. 



5. CHROOCOCCUS Niig. (1849). 



1. C. minutus Nag. Gatt. einz. Alg. 46 (1849); W. et G. S. 

 West, I.e. 



Protococcus minutits Kiitz. Phyc. Gener. 168 (1843). 

 HuiLLA. — In uliginosis editioribus prope Humpata, Empalanca et 

 Lopollo ; May 1860. No. 15. 



2. C. turgidus Nag., I.e. (1849) ; W. et G. S. West, I.e. 

 Protococeus turgichis Kiitz. Tab. Phyc. i. (1845-9), 5, t. 6. 

 HuiLLA. — In paludibus exsiccandis ; April 1860. No. 176- 



3. C. pallidus Niig., I.e., t. i. a, fig. 2 (1849); W. et G. S. 

 West, I.e. 



HuiLLA. — In uliginosis editioribus prope Humpata, Empalanca et 

 Lopollo ; May 1860. No. 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. feadio-purpureus W. et G. S. West in Journ. Bot. 1897, 

 p. 302. 



GoLUNGO Alto. — Inter Scytonema hisigne, ad rupes madidas in 

 umbrosis juxta rivum Coango inter Sange et Undelle : May 1856. 

 No. 5. Ad rupes juxta riv. Coango (N-della), crustam viscoso-carti- 

 lagineam fusco-badiam formans, Collematis thallum fingens ; June 

 1856. Nos. 139 and 140. 



Welwitsch contributed to the .Joui-nal 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 country, as it gives such a peculiar aspect to the 

 mountains that they are known as the " l)lack rocks." He writes 

 that it is " probably a non-described species of the prolific genus 

 Seytonema, which in that situation during the rainy season 

 generates and multiplies so rapidly that the upper portions of the 



