292 SUMMARY OF CURRENT RESEARCHES RELATING TO 



{Glceocapsa) and one witli encysted cylindrical cells (Gloeothece and 

 Aphanothece). A similar relationship has, in fact, already been sug- 

 gested by Naegeli in his ' Einzelligen Algen.' 



The form previously described by the author under the name 

 Aphanothece caldariorum presents an intermediate form between that 

 genus and Gloeothece, and would appear to be completed in its cycle of 

 development with two other forms named by A. Braun Gloeothece 

 inconspicua and Aphanocapsa nebulosa, being a maturer condition of the 

 first of these two. In the same way, A. Braun's Aphanocapsa hiformis 

 may be shown to occur in three different forms. 



The lowest form of the Phycochromaceje is the naked Aphano- 

 capsa condition, corresponding to PahneUa among the Chlorophyllo- 

 phyceae. From this naked or only slightly encysted condition is 

 developed the Gloeocapsa or Gloeocystis form with several gelatinous 

 envelopes ; the Chroococcus type, when the investment is altogether 

 wanting ; or, when there is only a single vesicular envelope, the coeno- 

 bium types. The Gloeocapsa type is specially adapted for exposure to 

 the air and growth upon a comparatively dry substratum ; the coeno- 

 bium type is developed in water ; the Chroococcus type in water or on a 

 moist substratum in the air. With this is connected the cylindrical 

 form, a higher stage, because it displays a differentiation in the direc- 

 tion of growth, and a development towards the filiform condition. 

 This is not always developed, and may be distinguished into stable and 

 unstable forms. The latter may occur in two or three varieties, and 

 may go through the foUomng successive conditions : — 



1. Stable Aphanocapsa and PahneUa. 



2. Aphanocapsa and PahneUa which have attained to Gloeocapsa, 

 Gloeocystis, or coenobium type, but which always revert to the naked 

 solitary spherical form. 



3. Stable Gloeocapsa, Gloeocystis, Chroococcus, and coenobium forms 

 without reversion {Merismopedia). 



4. Cylindrical forms, the generations of which pass through the 

 solitary spherical (Aphanocapsa and PahneUa) condition, as well as the 

 Gloeocapsa and similar forms. 



5. Cylindi'ical forms which pass through only the Gloeocapsa and 

 similar forms. 



6. Cylindrical forms, the generations of which revert to the 

 Aphanocapsa and PahneUa condition, while the Gloeocapsa or any 

 similar form is suppressed. 



7. Stable cylindrical forms (Synecococcus). 



No reference is made in the above to the passage of Gloeocapsa into 

 the encysted filiform conditions of Sirosiphon, corresponding to Pal- 

 modactylon and Ecemospora among the Chlorophyllophyceae. 



Crystalloids of Marine Algae.* — J. Klein enumerates fifteen 

 rioridese in which crystalloids have at present been found ; as also 

 one species of each of the genera Acetabiilaria, Bryopsis, Codium, 

 Dasycladus, and Cladophora. The most remarkable are those of 

 Dasycladus, which are large, brown, and distinctly striated. 



* Kleiu, J., " Neuere Daten ub. die Kiystalloide der l\Ieeres-a]gen." See 

 Bot. Ztg., xxxviii. (1880) p. 782. 



