95 



Syn. Spongites incrustans Ktitz. Spec. Alg p. 698. 



„ racemosa Kiitz. Phyc. gen. 386; Phyc. germ. p. 296; Spec. 

 Alg. p. 698? Cfr. Tab. Phyc. 19. p. 35. 

 Lithophyllum incrustans Aresch in J. Ag. Spec. Alg. 2. p. 519. 

 Lithothamnion crassum Unger, Leithakalk p.. 21, t. 5, fig. 9? 

 „ polymorphum Crn. Fl. Finist. p. 151. 



„ „ Le Jol. Liste Alg. Cherb. p. 151; saltern 



ex parte. 

 „ „ Rosan. Melob. p. 99 ; saltern ex parte. 



„ „ Hauck, Meeresalg. p. 271 ; saltern ex parte. 



Remark on the determination of the species. I have not the 

 ■advantage to decide with certainty what Philip pi has meant by 

 his L. incrustans. He refers to Corallina cretaceum lichenoides 

 Ell. Corall. p. 81, t. 27, fig. d. D., one of which is probably not 

 a Lithothamnion, the other not unlikely represents the species in 

 question, although the figure does not give any good idea of the 

 plant. Solms La u bach 1. c. declares L. incrustans in its typical 

 development to be easily recognized from the nearly allied L. po- 

 lymorphum Aresch., but it is on the other hand not quite evident 

 whether it really may be the same plant that I apprehend as L. 

 incrustans. Thus he remarks, that „die Conceptacula sind ausser- 

 lich nicht sichtbar" and that the surface is often sprinkled „mit 

 nadelstichartigen Lochern", which by Kiitzing is quoted as a 

 character of his Spongites confluens, the latter being considered by 

 Sol-ms Laubach identical with L. incrustans, and these holes 

 he states to be „nur die Mundungen zahlreicher, von Thieren ge- 

 bohrter Gange". In this respect the plant in the sense here taken 

 quite differs from that of Solms Laubach. The conceptacles 

 of sporangia are, as below mentioned, visible from the surface of 

 the frond just as small pin-holes, but they are, on the other hand, 

 particularly when emptied, easily confounded with passages made 

 by worms, which certainly are often to be found in this as well 

 as in all or nearly all other species. He records as a well marked 

 character, that L. incrustans distinguishes itself by the colour of 

 a fracture of the frond. ' „Auf dem Querbruch ist er schmutzig- 

 weiss .... Normal entwickelte Individuen beider Arten gleichen 

 sich vollkommen, lassen sich aber in frischen Zustand sofort an 



