In List of Species of the Lithothamnia^) I quoted a number 

 of species which were quite unknown to me, and others the range 

 of which seemed to be rather uncertain. Among these are some 

 species described by Crouan in Ann. se. nat. and Fl. Finist. I 

 have now, hovvever, had the opportunity to examine as far as I know 

 nearly all the unarticulated calcareous algæ recorded by Crouan 

 from the coast of France, thanks to the liberality of Dr. Bornet and 

 Mr. Hariot, who have been so kind as to send me specimens for 

 examination from Crouans herbarium, or distributed by himself 



The species belonging to the genus Litliotliamnion as formerly 

 limited have been mentioned partly in Norwegian Forms of Litho- 

 thamnion partl}^ in later papers. 'J"herefore, I want here only to 

 mention most of the species of Melohesia and Hcqjalidmm as 

 comprehended by Crouan, as well as a few species of other au- 

 thors in connection with the former. 



Hapalidium zonale Crn. 



in Ann. se. nat. p. 284, pl. 21, f. A. 1—7.2); fi_ pinist. p. 149. 



= Melobesia (Heteroderma^) zonalis (Crn.) Fosl. 



A specimen of this species in Museum d'histoire naturelle di- 

 stributed by Crouan that I have seen is attached to a piece of 



1) Det kgl. norske \'idenskabers Selskabs Skrifter. 1898. No. 3. 



2) Crouan fréres. Notise sur le genie Hapalidium. Annales des sciences 

 naturelles. Botanique. Ser. 4. T. 12. 



3) Heteroderma , which is nearly connected with GomoIitJion, includes species 

 with more layers of cells, contrary to Eumelohesia with only one layer 

 except where conceptacles are formed, and minute cortical cells each of 

 which covering only a part of the basal cell. However, I am not yet sure 

 as regards its relation to GoniolitliOn. 



