742 SUMMARY OF CURRENT RESEARCHES RELATING TO 



again and remain together, forming a colony of eight cells enclosed in a 

 gelatinous envelope, as in Chromidina Hokeana. Already in such primi- 

 tive cases of colony-formation the form of the future colonies is indicated. 

 Such types are represented by Goniuni, Eudorina, Pandorina, Stephano- 

 sphsera, etc. The individuals become fixed, the gelatinous envelope 

 takes on certain characteristics and structure, and becomes less labile. 

 The genesis of colony-formation in the Flagellates is shown in tabulated 

 form, founded on the stages observed. Finally, descriptions of the new 

 species of Chrysomonads are given in German. 



New Parasitic Alga.* — Th. Mortensen and L. K. Rosenvinge 

 describe a species of alga which is parasitic on the animal Ophioglypha 

 texturata Lank., observed by the former author in the Limfjord. A 

 description is first given by Th. Mortensen of the relation between the 

 parasite and the host, and this is followed by Rosenvinge's description 

 of the alga itself. The particular interest of this species lies in the fact 

 that it is the first example known of an alga which is truly parasitic 

 on an animal. Instances are known of algse living in symbiosis with 

 animals, but no instance has been known hitherto of an alga which 

 caused such illness on an animal that death was the result. The alga, 

 Coccomyxa Ophiurse, is described and figured. 



Phylogeny and Inter-relationship of the Green Algse.t— F. E. 

 Fritsch discusses the phylogeny and inter-relationships'of the green algae, 

 indicating briefly the diverse lines of evolution that can at present be 

 traced among the green algas, and considering their connexion with the 

 Flagellatre. He also describes the salient features in the structure and 

 life-history of the forms. He gives a digest of the works of other 

 authors and appends a bibliography of seventy-one items. The relation- 

 ship of the different groups is shown diagrammatically in a table. 



Stauroneis Terryi. $ — T. C. Palmer describes and figures an anomalous 

 diatom collected in Connecticut and published at first as Stauroneis acuta 

 W. Smith, var. Terryana Tempere, the description being very short and 

 inadequate. Later it was fully described by D. B. Ward as S. Terryi. 

 The peculiarities of this species are that (1) it is the largest by far of 

 the genus Stauroneis ; (2) it is the only one of the genus to show sub- 

 terminal depressions on the valves ; (3) it is the only naviculoid diatom 

 known that has a siliceous belt about its middle part. The author proves 

 that S. Terryi cannot be a sport or monstrosity ; but its relationship is so 

 close to S. acuta that it may possibly represent a sporangial condition of 

 that species. That view 7 would explain the comparative rarity of the 

 diatom in Terry's gatherings. But on the other hand one would expect 

 them to find among all the material some indication of the process of 

 return to normal form. Nothing of the sort has yet been seen, how- 

 ever. More and living material is necessary to solve the problems 

 connected with the species. 



* Overs, k. Dansk. Vidensk. Selsk. Fork., 1910, pp. 339-49. 



t Science Progress, No. 16 (1910) pp. 623-48 ; No. 17 (1910) pp. 91-110 (figs.). 



X Proc. Acad. Nat. Sci. Philadelphia, 1910, pp. 456-9 (pi.). 



