Bd. IV: 5) ANTARCTIC AND SUKANTARCTIC CORALLINACE.^i. II 



f. coinpacta FüSL. 

 Alg. Not. 1. c. : tab. nostr. 2, fig. 5. 



Syn. Lithophyllum capitulatum Heydr. Lithoth. Exp. antaret. Kelge in liull. Ac. R. 

 Belg. 1900, p. 560! 



The form w hieb I bave denominated f. circuntscripta is in fact onl)- represented 

 by young or feebly developed specimens of the species sucli as it was first under 

 consideration, and such as it was first described. It is, therefore, questionable whether 

 it OLight to be looked upon as an independent form. Indeed, it is morc regularly 

 orbicular than young specimens of f. iypica, and the conceptacles are partly a little 

 smaller. But still no proper line can be drawn, to judge from the material in band. 

 The form corresponds to certain forms of Lithophyllmn incrustans, as on the whole 

 L. JiscoidcHvi corresponds to and approaches the said northern species. 



The form I consider as the typical form of the species, is a rather coarse one, 

 but. when young, it shows the same state of things as the form last mentioned, 

 forming more or less orbicular crusts, which are, however, apt to be sooner con- 

 fluent than those of the said form. When, in growing, the crusts come in contact, 

 the edges colliding are frequentl)- curved upwards and against each other, and gather 

 in dense, interlocking folds, the surface of which finally coalesces. The same is the 

 case even to a higher degree with some other species, e. g. Lithopliylluvt incrustans 

 and Phyiiiatolitlion lociilosmii, sometimes also P/i. polymorpliuiii. Besides, the crust 

 often develops irregulär and rather coarse excrescences. This form recalls in habit 

 peculiarly intermediate forms of Lithoph. incrustans f. Harvevi and f. angiilata. 



Of the form covipacta only a single specialen is known. The form is closely 

 connected with f. Iypica, but is distinguished b\- conceptacles more depressed, by 

 the greater thickness of the crust, which is up to 3 cm., and particularly by its 

 firmer consistenc)-. It bears in habit a close resemblance to coarse and smooth forms 

 of Pliyinatolitlion {Clathroinorpluiui) conipactian and locnlosnm. 



As I already mentioned in the first description, the species is rather varying as 

 to structurc. Thus the perithallic cells, particularly in f. circumscripta, are often 

 shorter verticalK- than in other forms. Also in this respect /,. discoideinn shows 

 almost the same State of things as L. incrustans, the corresponding cells of f. de- 

 prcssa of the species last mentioned being frequently much shorter than usual in 

 e. g. f. angulata. On the other band small intermediate cells occur now and then 

 in L. discoideiint as in ArclurolitliotIiainnio)i. This is never the case with L. in- 

 crnstai/s. 



The conceptacles of sporangia in this species, when seen from the surface, are 

 first slightly convex, 180 — 250 ,(( or up to 300 /< in diameter. Then they are fre- 

 quently decorticated and forming small point-Iike holes, as in Lithoph. incrustans, 

 tiiough shallower ones than in the iatter. In a median vertical section they are 



