14 HENRIK PRINT Z [1920 



cedanee ortis, qnae solitarie per poriim membranac nvdernae 

 Uberantur. 



Myrmecia globosa iiov. spec. [PI. II, Fig. 105 — 123]. 



Cellulis subrotiinde-ovalibus libere et soUtdiie viventibus el 

 adultis vulgo 16 — 19 «. Membrana achroa, crassiuscnhi, vulgo fere 

 2 u crassci et tatere uno in verrucam hiimitem, tcdam incrnssala. 

 Cnromatophoro campanulato, parietati, totiim parictem interiorem 

 obtegente vel interdum uno ledere, vulgo membranae incrasscdae 

 opposUo, inciso. Pyrenoidibus nullis. Nucleo pro ratione magno. 

 centrali. Propagcdio zoosporis contentu cellulae mcdernae diviso 

 succedanee ortis, zoosporis elongcde-ovatis, 3 — 3,5 ji( longis et 

 stigmate distincte instructis. Per porum membranae maternae 

 solitarie Uberantur. Alga aéris in cortice nrborum crescens. 



This alga much recalls Kentrosphaera in the shape of the oeliLs. 

 This likeness is oiil}^ seeming, however, and is niainly tlue Lo ithe 

 exleriial habitus of tbe cells, with a thdok wall and a 1>1liiiI, conical 

 or papilliform excrescenoe. In the inner structure Myrmecia globosa 

 differs distinctly from Kentrosphaera, thuswise in ils chronialo- 

 phore, which is a parietal cup, lining nearly the whole of the 

 cell-wall, while in Kentrosphaera the chromatophore is radiate. 

 formed by numerous parietal slabs or ribbon-shaped rays. To the 

 structure of the chromatophore there must be attached great 

 importance in a case like this. Of other differences from 

 Kentrosphaera must further be noticed the absence ofapyrenoid,th( 

 smaller number of zoosporeis, formed by s u c c e d a n e o u s divi- 

 sions. In Kentrosphaera the divisions are s i m u 1 t a n e o u s in a 

 far greater number of zoospores. 



The inner structure of the cells shows, oii the other band, a 

 more close conformily to Chlorococcum, a genus which I considea- 

 as being one of the most nearly allied ones. The most esseniial 

 difference from Chlorococcum is the thick membrane, with n 

 unilateral projection, and the absence of a pyrenoid, in so far as this 

 last feature is to be considered as being of any system.itical value. 

 As the inspissation of the membrane of Myrmecia globosa is 

 a unilateral excrescence only, onie often has to displaoe,in la prepara- 

 tion of tilis kind, the cells by meians of a jjressure on the cover gliass 

 in order to get sight of it. It is commonly compiaratively lower 

 and broader than usual in Kentrosphaera; in young cells it may 

 even be conspicuous and of comparatively oonsideirable dimensions 

 (e. g. fig. 114, pi. II). The membrane is colourless and rather thick. 

 its thickness being somewhat varying, usually ± 2 jn, and without 

 any particularly pronounced stratification. Treated wilh chlor- 

 iodide of zinc, it assumes a slightly violet tint. In the cup-shaped 

 chromatophore Ibere is no pyrenoid; on the other hånd, there miay 

 be observed one or more dark spots, which probably are products ol 



