SUMMAEY OF CURRENT RESEARCHES RELATING TO 



Of undoubtedly endoplastic organisms in this coal there are four 

 distinct forms: — (1) Short vermiform cells rounded at the end; 

 these present the greatest resemblance to endophytic Saprolegnieas. 

 (2 ) Elongated vermifurm cells ; their nature is uncertain. (3) Peculiar 

 endophytic (?) forms of unknown nature. (4) Peculiar true filiform 

 endophytes within separate Tir/Ze/es-structures. 



The epiphytal organisms which occur on one particular kind of 

 the lamella of this coal present a strong resemblance to certain very 

 simple organisms of the nature of Zoogloea occurring on marine 

 algse. 



Sphseroplea annulina.* — N. W. P. Eauwenhoff gives an account 

 of his researches ou SphcEropha annulina Ag., an alga belonging to 

 the oogamic Confervoidefe. Besides confirming in great measure the 

 results of Cohn, he has discovered many peculiarities " which appear 

 to him to have a certain importance, because they may contribute to 

 the elucidation and solution of some interesting problems of the 

 day." 



1st. The filaments of SjjJiceroplea annulina, long, thin, and terminat- 

 ing in a point at both ends, are divided at greater or less distances 

 by transverse septa, which look like thick bars of irregular form 

 with all sorts of excrescences and jDrotuberances. The>e bars, of a 

 very marked brilliancy and double refractive power, consist of pure 

 cellulose, and show difi'erent layers. They originate in the form of 

 rings or excrescences on the internal face of the cell-wall, and 

 either remain open in the middle or close up later on, beginning 

 either at one side only or at both, by a kind of large plug of cellulose. 

 These bars, as much from their structure as the manner of their 

 formation, may perhaps be considered as a proof of increase by 

 apposition, similar to the bars of Caiderpa, cited by Dippel and 

 Strasburger in support of their view. 



2nd. Nuclei are not found in the cells of Sphceroplea, but many 

 chromatophores with starch granules. From the time of the longi- 

 tudinal growth of the cells, the chromatophores divide, and at the 

 same time the number of rings of chlorophyll increases. In various 

 parts of the bars a dense accumulation of these chromatophores is 

 seen united to the bars by thin and colourless protoj)lasmic fila- 

 ments. "When the oosphercs are being formed, the chromatophores 

 and the colourless plasma are reunited in dense, irregular, granular 

 masses, as if suspended in the cavity of the cell by slender proto- 

 plasmic threads, and separated from one another by thin, but sharply 

 defined, protoplasmic disks which completely disappear later on. 



3rd. From the time of the formation of the spermatozoids, the 

 chromatophores lose their green colour and gi'adually become light 

 brown, at the same time that they break up, together wdth the plasma, 

 into a multitude of small grains. In the beginning the regular rings 

 persist ; but the whole of the protoplasm is gradually sejiarated into 

 a limpid liq^uid and numerous microsomes, which are principally 



* Eev. Interuat. Sci. Biol., xii. (18S.3j pp. 176-7. Paper read before the 

 Amsterdam Academy on the 2Gtli Mny, 1883. 



