102 KJELLMAN, THE ALGA OF THE ARCTIC SEA. 
of small holes perceptible to the naked eye. I have not seen specimens with sporo- 
carps, nor any with mature sporangia. Thus I know nothing about the shape and size 
of these. 
Relation to other species. Amongst the species of Lithothamnion that I know, the 
present species exhibits the greatest resemblance to Lithophyllum incrustans Pain. Argscu. 
Cp. Solms-Laubach, Corall. Monog. p. 16. In structure, however, it differs essentially 
from this. 
Habitat. It clothes rocky ledges to a large extent in the upper part of the sub- 
litoral zone, and stones and Lithothamnia in the lower part of the same region. I 
have found it down to a depth of 15 fathoms on stony bottom. It seems to prefer 
sheltered places. I do not know at what season it bears ripe spores. The specimens 
examined by me, were collected at the end of June and during the latter part of July. 
Geogr. Distrib. Hitherto known only from the arctic region of the Polar Sea. 
Its most northern place of growth is Karmakul Bay on the west coast of Novaya 
Zemlya, about 72° 30' N. Lat. 
Localities: The Murman Sea: in Karmakul Bay and Kostin Shar on the west coast 
of Novaya Zemlya, in both places rather plentiful, though local. 
Lithothamnion polymorphum (L.) Arrscu. 
In J. G. Ac. Spee. Alg. 2, p. 524; Millepora polymorpha L. Syst. Nat. p. 1285; ex parte. 
Descr. Lithothamnion polymorphum Soums-Lausacu, Corall. Monogr. p. 16—17, sub Lithophyllo incrustante. 
Fig. » » Hauck, Meeresalg. t. 1, fig. 4. 
Exsicc. » » Arescu. Alg. Scand. exsicc. N:o 302. 
Syn. Lithothamnion polymorphum Ktigren, Nord]. Alg. p. 11, non Argscu. Obs. Phyc. 3, p. 5, quoad 
plantam Spetsbergensem, nec KseLim. Algenv. Murm. Meer. p. 8, Kariska hafvets algv. p. 15. 
» Melobesia polymorpha Croa.u, Fl. Disc. p. 459. 
» » » Dickie, Alg. Sutherl. 1, p. 142; 2, p. 192. (?) 
Remark on the synonomy. It has been the general practice of algologists to unite 
all or nearly all crust-like Lithothamnia into a single species, LZ. polymorphum. I have 
also been guilty of this fault. Having now had the advantage of examining more 
thoroughly a greater number of specimens, I am however perfectly convinced that 
such a proceeding is incorrect and that there are among the crustaceous Lithothamnia 
several well marked and easily characterized species. I have above brought into view 
some species from the Arctic Sea, and I hope soon to get an opportunity of elucidating 
the two or three species occurring on the west coast of Sweden, but referred by all 
Swedish algologists to the same species, L. polymorphum. On account of the uncritical 
treatment these plants have been subjected to, it is impossible, without having access 
to original specimens, to determine what an author has meant by a plant called by 
him L. polymorphum. A plant thus named kas been reported from the American 
Arctic Sea, but as no specimens of it have been at my command, I refer it only with 
hesitation to the species of LZ. polymorphum, as I understand it here. This is also the 
case in some degree with respect to that Corallinea which is mentioned by CRoaut in 
