F. E. Fritsch. 
34 6 
Flagellate character is also emphasised by its longitudinal division. 
No form provided with an envelope is however yet known among 
the Polyblepharidaceae, and 1 am doubtful whether a useful purpose 
would be served by placing Isococcus in this family. Although one 
is naturally reluctant to multiply the number of families, it would 
perhaps he best for the present to place Isococcus in a family by itself, 
the Isococcaceae. When further details of the life-history are 
forthcoming the new genus may secure another position. It is not 
impossible, for instance, that it may he a reduced member of 
Chlamydomonadacese which has secondarily become naked—alight 
in which Pascher regards Teodoresco’s Dunaliella. 1 
II. Chrysococcus tessellatus n. sp. (Fig. 3, F, G). 
This form occurred in the same locality as the last but was 
only observed in very small numbers, so that I cannot pretend to 
more than a scanty acquaintance with it. The envelope is colour¬ 
less and spherical (about 1 4y, in diameter) except at the front end, 
where it is slightly protruded to form the small circular cilial 
aperture from which the single delicate flagellum projects (Fig. 3, F). 
The envelope is almost completely filled by the protoplast, rather 
more than half of which (the back half) however is occupied by a 
large mass of highly refractive leucosin. Anterior to this, the 
periplast exhibits a very characteristic tessellate structure, being 
provided with numerous small round densely placed sculpturings 
which give a very distinctive appearance to the whole front part 
of the protoplast (Fig. 3, F). There are two brown-coloured 
plastids placed symmetrically (one on either side) with reference to 
the cilial aperture of the envelope (cf. Fig. 3, G); these plastids are 
of remarkably small size and are seen through the characteristic 
tessellation of the periplast. No other details of the cell-structure 
could he determined, nor were reproductive stages observed. 
Chrysococcus tessellatus is distinguished from all the species of 
the genus hitherto described by the structure of its periplast and 
the small size of its plastids. The latter feature is of special interest, 
as it may indicate a tendency towards reduction of plastids, such as 
has undoubtedly occurred in the case of other Chrysomonadinese 2 . 
III. On Some Forms of CRYPTOMONAS (Fig. 2, A-H). 
Species of Cryptomouas are perhaps, apart from the Euglenineae, 
the commonest Flagellates to be encountered in small pieces of water. 
' Pascher, “ Kleine Beitrage zur Kenntnis unserer Mikroflora, I. Zur 
Kenntnis zweier Volvokalen.” Hcdvvigia, Bd. 52, 1912, p. 283. 
* Cf. Pascher, “ fiber Rhizopoden-und Palmeliastadien bei Flagellaten 
(Chrysomonaden).” Archiv f. Protistenkunde, Bd. 25, 1912, p. 189 ; Scherffel, 
“ Beitrage zur Kenntnis der Chrysomonadinen.” Ibid., Bd. 22, 1911, p. 327. 
