QUARTERLY CHRONICLE. 31 



fibrils of ■which the thicker filaments are composed are all 

 produced from the fusiform corpuscles. The whole network, 

 in fact, may be described as a gelatinous, fibrillated secretion 

 of the corpuscles. 



The second species, L. macrocystis, agrees with the former 

 in all essential particulars of strvicture, &c. Its corpuscles, 

 however, are somewhat larger (0"018 — 0"025 mm.) and of 

 denser consistence ; the nucleus is better defined, and the 

 contents more granular and colourless, or with the faintest 

 yellow tinge. The cells constituting the central mass have 

 in this species usually an arched or curved form, with rounded 

 ends, and the convexity directed towards the periphery of 

 the mass. When viewed with a pocket lens, the masses 

 appear as white or yellowish gelatinous drops, which are 

 sometimes aggregated into vermiform growths which are 

 seen, several together, on various parts of the algan incrusta- 

 tion. 



In further illustration of the nature of the Labyrinthuleag, 

 the author states that the fusiform corpuscles multiply by 

 division, the first indication of which is the formation of a 

 septum, usually running obliquely across the cell in the line 

 of its future scission. In this process the nucleus does not 

 divide, but a new nucleus is formed in one of the segments. 



Under certain circumstances, as, for instance, when exposed 

 to partial desiccation, L. macrocystis has the power of very 

 readily becoming quiescent, that is to say, of becoming 

 encysted, in which condition it may remain for many weeks 

 imchanged. 



3. " On Clathrulina, a New Actinophryan Getius,'^ by Pro- 

 fessor L. Cienkowski. The groAvths to which the name of 

 Clathruliyia has been applied, and of which it would seem 

 Professor Cienkowski has distinguished two species, or rather 

 varieties, consist of protoplasmic masses, lodged free within a 

 fenestrated shell, through the wide openings of which the 

 numerous pointed pseudopodiap)roject, and which is supported 

 on a long, rigid peduncle, by which it is affixed to various 

 subaqueous objects. The shell or case also not unfrequently 

 itself forms the basis of support of the peduncles of other 

 Clathrulina disposed in a radial manner, and again serving 

 for the support of a second series, and so on. 



It was in this aggregated form that the author first dis- 

 covered the genus about ten yeai:s since in St. Petersburg, in 

 a tank containing Nitella, Vaucheria, &c. ; and he has since 

 observed it in Dresden, Franzensbad, but very rarely, and in 

 small quantity. The groAvth may be simply described as an 

 Actinophrys contained in a fenestrated case of a globular or 



