364 T. JEFFREY BELL. 



into one intensely alkaline, due apparently to the presence 

 of free ammonia, which is very easily recognisable. 



Although Cohn is not quite certain as to whether this 

 form is really the same as that which Billroth has already 

 called by this name, he thinks it probable that it is so ; in 

 any case he thinks his form one of generic value, and adds 

 the following diagnosis of its characters : 



Ascococcus, Billroth, char, emend. Cellulce achromatic^ 

 minimcB globosce densissim,e consociatee infamilias tuberculosas 

 globosas vel ovales irregulariter lobatas, lobis in lobulos 

 minores sectis, capsula globosa vel ovali gelatinosa cartilaginea 

 crassissima circumdatas, in memhranam mollem facile sece- 

 dentem floccosam aggregatas. 



A. BiLLROTHii, n. sp., familice tuberculosa 20 — 160 

 mikrom. capsula ad 15 mikrom. crassce. In solutione ammonii 

 tartarici acidi acre lavata sponte ortum, memhranam odore 

 lacticovel butyrico prceditam formantem observavi Mart. 1874. 

 Haud scio utrum eandem an affinem speciem ill. Billroth in 

 aqua carnis fcetida detexerit. 



4. Although, at first sight, the developmental history of 

 Ascococcus is so remarkably strange, it appears to fill up a 

 blank in the relations of the genus Micrococcus to the family 

 of the Chroococcacece ; for, in this family, there are forms 

 either spherical or cylindrical, solitary or loosely connected, 

 or forming distinctly limited colonies united by membranous 

 intercellular substance ; the genera Glnsothece, Microcystis, 

 Polycoccus, and Anacysiis, for example, make solid balls 

 formed of very small round cells, united by intercellular 

 substance, and surrounded by an envelope of varying thick- 

 ness ; in Polycystis there are found several Microcystis colo- 

 nies, with a common investment; while in Coelospharium 

 the cells are found only at the periphery of the membrane, 

 and so form a hollow sphere. Now, while Ascococcus is 

 separable from Microcystis, Anacystis, and Polycystis, by the 

 absence of colour in its cells, the developmental history of 

 Coelospharium, as related by Naegeli, Unger, and specially 

 Leitgeb, is strikingly analogous to that of Ascococcus ; ^ C. 

 Naegelianum, Unger, is a free-swimming form found on the 

 surface of a pond at Graz, the cell-families of which form 

 hollow spheres ; these may unite to form 2 — 6 spheres with 

 flattened edges ; with furrows, more or less deep, and more 

 numerous as the families are larger, on the surface ; cell 

 gradations between families with altogether indistinct fur- 



^ Cohn pives the following references : Unger, ' Deukschriften der K. 

 Akad. der Wiss.' Band. vii. Leitgeb, Mittheil. der naturwiss. Vereins fiir 

 Steiermark. Bd. ii. Heft 1, 1869. Tab. 11. 



