180 SOME NEW OK LESS KNOWN DESMIDS FOUND IN N. S. WALES, 



Xan. bifurcatum Borge, in Bailey, Bob. Bull, xv., T.14, f.6. 

 (T.iv. f.8, 9). 



Long. c. proc, 132-250; lat. c. proc. 84-165; lat. coll. 33-60; long, 

 s. proc. 93-220; lat. s. proc. 50-125; long, proc. 15-22/z. 



Centennial Park. 



The specimen figured shows one semicell undeveloped (fig. 9) 

 and the other naature. In the young form the processes are 

 solitary, not in pairs. The endochrome is arranged in 6 parietal 

 fillets. 



Xan. pulcherrimum, n.sp. (T.iv. f.lO). 



Xan. magnum, subduplo longius quam latum, medio sinu 

 cuneato introrsum acuto non lineari, profunde constrictum. 

 Semicellulae euneatae; basi lato; lateribus levissime retusis; 

 apicibus truncatis leviter retusis; angulis inferioribus in pro- 

 cessus geminatos productis et infra marginem insuper processibus 

 singulis; apice processibus 6 concentrice ordinatis, ornato, pro- 

 cessubus 4-fidis omnibus. Semicellulae in centre nudae; a latere 

 visae ovatae, apicibus processibus munitis; a vertice late ellipticae, 

 paullo in medio utrinque inflatae; apicibus processibus 3 instructis. 

 Membrana subtilissime punctata. Endochroma in taenias 6 longi- 

 tudinaliter disposita. 



Long, c proc. 257; sine proc. 224; long. proc. ad 22; lat. c. proc. 

 156; sine proc. 116 : crass. 82jm. 



Lara Dam, Moura. 



I had at first thought that this species might be the immature 

 form of X. bifurcatum, to which class of Xan. it belongs. The 

 young semicell of that species, however, as shown in T.iv. f.9, has 

 the same 3-lobed outline as the mature form, whereas in X. pul- 

 cherr'imum the semicell is decidedly cuneate, and also there are 

 no processes at all in the centre 



Xan. hexagonum, n.sp. (T.iv. f.ll). 



Xan. mediocre, subrectangulare, circ. tam longum quam latum, 

 medio sinu lineari extremo ampliato profunde constrictum. 

 Semicellulae oblongae, subhexagonae; angulis inferioribus fere 

 rectis; lateribus levissime retusis, e basi lato verticalibus turn 



