ATLAS DEUTSCHER MEERESALGEN. 61 



which Dr. Keinke is known to be a special authority. As a rule 

 every species is illustrated by a life-size drawing, and by a series 

 of microscopic figures, under various powers, showing every part 

 of the structure, and, so far as is possible, all stages of develop- 

 ment. The figures are remarkable for their minute accuracy, 

 and it will be noticed that special attention is paid to the form 

 and distribution of the chromatophores. An English botanist on 

 looking at these plates may well feel envious, and wish that our own 

 far richer algal flora could be illustrated in the same thoroughly 

 scientific manner. Let us trust that this wish will eventually 

 bring about its own realization. 



We will notice a few of the more important forms specially. 

 Halothrix is a new genus founded by Dr. Eeinke, for the species 

 H. lumbricalis (pi. 1), placed by Kiitzing in Ectocarpus, and trans- 

 ferred by Hauck to Elachista. The genus comes very near 

 Giraudia, but the upright assimilating filaments are usually 

 monosiphonous. Only plurilocular sporangia are known, which 

 are developed in sori on the upper parts of these filaments. The 

 central portion of the mother-cell of each sorus divides up to a 

 certain extent, but remains sterile. 



The next genus, Symphoricoccus, is founded on a species S. radians, 

 discovered by Dr. Eeinke. It is closely related to Elachista, but 

 differs from that genus in the fact that the unilocular sporangia 

 (here the only kind known) occur on the upper part, as well as at 

 the base of the assimilating filaments. It is interesting to note 

 that here a small cell is cut off at the base of each sporangium; this 

 cell grows out into the cavity of the old sporangium when it is 

 empty, forming a new one to replace it. Much the same process 

 has long been known to occur in Cladostephus. 



Kjellmannia Eke. is an interesting genus placed by its author in 

 the group Punctariea3. The branched polysiphonous thallus bears 

 short monosiphonous branches. There are two kinds of sporangia, 

 both plurilocular, one kind intercalary, the other in sori. Like its 

 near relations this genus has no definite growing point, the 

 intercalary growth going on indiscriminately in all regions. 



Passing over some forms of Asperococcus and Ralfsia, of less 

 general interest, we come to Microspongium gelatinosum Eke. 

 (Pis. 7 and 8.) This is the type of a new genus of Myrionerneae, 

 coming next to Ascocyclus Magn. There is a basal disc, two cells 

 thick, with marginal growth. From this arise vertical hairs and 

 assimilating filaments. The latter have a chiefly apical growth, 

 a fact which shows how little importance can be attached to this 

 character among the Pheeosporeaa. Plurilocular and unilocular 

 sporangia are formed on distinct plants, but it is not absolutely 

 certain that these forms are specifically identical. 



In plates 9 and 10, three varieties of Leptonema fasciculatum 

 Eke. are figured. Leptonema is a new Elachisteous genus, placed next 

 Halothrix. From a creeping protonema arise assimilating fila- 

 ments only branched at the base. Growth is intercalary and 

 basipetal as in the group generally. Both kinds of sporangia 

 occur. The unilocular sporangia arise laterally, close to the base 



