ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
79 
less well-represented. Further material examined after the death of the 
former of the two authors showed several more or less complete stem- 
nodes with small portions of the internodes and branches attached. Two 
types are represented, the first resembling Ghara canescens among living 
species. The second type resembles Ghara imperfecta, except that the 
fossil species has fairly large stipulodes, while in the living species these 
are rudimentary. E. S. G. 
Marine Algae of Denmark. Contributions to their Natural 
History. Part II. Rhodophyceae : II. (Cryptonemiales). — L. K. 
Rosenvinge ( K . DansJc. Vidensk. Selsk. Skrift., vii. Ser., tom. 7, 2, 
155-283, 2 pis. and 128 figs.). An important contribution to our 
knowledge of many species of Cryptonemiales. The forty species 
recorded belong to Dnmontiaceae, Nemastomataceae, Rhizophyllidaceae, 
Squamariaceae, Hildenbrandiaceae, Corallinaceae and Gloiosiphoniaceae. 
The structure of the thallus and the structure and development of the 
reproductive organs are described and figured for most of the species ; 
also their distribution in Danish waters. Two new species of 
Squamariaceae are described and the sexual organs of four known 
species. The family Hildenbrandiaceae is here restored, characterized 
by the absence of lime, by immersed sporangia, and by oblique divisions 
of the sporangia. The development of the immersed sporangia is 
described. In Corallinaceae the fusion of cells, by means of pores in 
the transverse and vertical walls, is discussed, a process which may be 
followed by fusion of nuclei. Hyaline hairs occur in Melohesia , 
Lithophyllum and Gorallina ; the cells producing them are called by the 
author “ trichocytes ” and are the heterocysts of Rosanoff . The 
structure and development of the sporangia of G. officinalis are 
described, as also the antheridia of Lithothamnion Lenormandi. In 
Lithophyllum Gorallinse the isolated spermatia found in the conceptacle 
contained two nuclei ; a number hitherto observed only in spermatia 
when fixed to the trichogyne and not earlier. An aberrant position of 
carpospores was noticed in certain species. Five new species of 
Melohesia are described. This genus can be distinguished from 
Dermatolithon , a subgenus of Lithophyllum , by the absence of transverse 
pores between the upright celbseries proceeding from the basal layer in 
Melohesia , and their presence in all species of Lithophyllum. The 
germination and development of the antheridia is described in 
Gloiosiphonia capillaris. The paper closes with some general remarks 
on Cryptonemiales. Intercalary cell-division has been observed in 
Dumontia incrassata and Hildenhrandia prototypus ; and cell-fusion in 
Squamariaceae. Alternation of generations and alternation of nuclear 
phases are discussed. Observations made on Furcellaria fastiqiata and 
Petrocelis Kennedyi point to a possibility of parthenogenesis. In 
Petrocdis Kennedyi and Cruoria pellita tetraspores and sexual organs 
have been met with in the same individual. In all these cases it must 
be presumed that the tetrasporangia are formed without reduction of 
chromosomes. Finally, the author opposes Svedelius’ suggestion that 
cruciate tetrasporangia are possibly always produced without reduction 
of chromosomes. E. S. G. 
