63 



up to about 10 u.. long. The crusts are rather young, but fertile, and similar young crusts are 

 to be found in the form attached to the other piece of wood mentioned. Thus the difference 

 lies principally in the consistency and partly the structure too. 



This species is easily recognizable, but, as I have remarked under Lithothamnion 

 erubescens, it may be questionable whether the plant is in fact distinguishable from Lithophylhixa. 

 decipicns from the south coast of South America. There are up to the present known but a 

 few specimens of the latter. It seems to be a little differing particularly as to structure. L. 

 Yendoi also comes very near to L. subtenellum from the southern Atlantic coast of Europe 

 and the western coast of Africa. It is furnished with reproductive organs in the months of 

 April to June, August to September, and in November. 



Occurrence: Only one or up to three specimens are known from each station. The 

 plant has been best and most typically developed at the stations 51, 155 and 193. 



Area: North Pacific: The Carolines, the Pacific coast of middle Japan and the Gulf ofSiam. 



b. Subramosa. 



4. Lithophyllum papillosum (Zan.) Fosl. 



Rev. Syst. Surv. Melob. p. 20. 



Lithothamnion papillosum Zan. Saggio p. 43 (sine descr.); Hauck, Meeresalg. p. 272, t. II, fig. 4. 



f. Cystosirae (Hauck) Fosl. 



Lithoth. Adriat. Meer. 



Melobesia Cystosirae, Hauck I. c. p. 266, t. III, fig. 1, 2, 6. 



Melobesia (?) Cystosirae Fosl. Rev. Syst. Surv. Melob. p. 21. 



Stat. 282. Between Nusa Besi and the N.E.-point of Timor. 27 — 54 m. Sand, coral and 

 Lithothamnion. 



As mentioned 1. c. I have been unable to draw any true limit between Melobesia Cystosirae 

 and Lithophyllum papillosum. Therefore, I placed the former as a form of the latter. In the 

 Adriatic the plant sticks to stones or other hard objects, e. g. shells of molluscs or a conglo- 

 merate of Serpulides and calcareous sediments. Besides it is fastened to Cyslosira, exceptionally 

 to filiform algae heaped together, and it has also been 

 met with on the branches of Lithothamnion J ' rutiailosum. 



In the Sibog^a collection occurs a small and frag- 

 mentary, almost quite even crust about 3 mm. in diameter 

 and 0,2 — 0,4 mm. thick. It sticks to a fragment of a 

 branch of Archaeolithothamnion sp. With some doubt 

 I refer this crust to f. Cystosirae, to which it agrees in 

 structure. It must, however, be borne in mind that the 

 species in question is much varying in this respect, and 

 the cells are often longer than in the said crust, but often also of exactly the same shape and 

 size. The hypothallium in this species is formed partly by a solitary row of oblique cells, partly 



Fig. 23. Lithophyllum papillosum (Zan.) Fosl. forma. 

 Vevtical section of the crust; X 72. 



