BY G. I. PLAYFAIR. 813 



smaller plate is always on the left in end view from the ventral 

 side. This is the only European type I have so far noted here. 



Var. botanicum, n. var. (PI. xli., f. 3). 



Forma in eonspectu dorsali fere circulata nee ad latera pro- 

 tracta; hypovalva a tergo spinis minutis binis armata; fossa 

 longitudinali magis distincte definita. 



Long. 42-60, lat. 40-60, epiv. alt. 21-30, crass. 30-37 ^ 



Botanic Gardens (3) ; Botany (17) ; Canley Vale (94) ; Guild- 

 ford (70, 77) ; Fairfield (83) ; Sydney Water Supply (100, 115) ; 

 Lismore (332, 333). 



Syn. Peridinium tabulatum in Plankt. Sydney Water Supply, 

 p. 452, PI. lvii., f . 1-3. In this form the cell in dorsal view is 

 almost circular, the margins of the transverse furrow projecting 

 very distinctly; the cell is not produced laterally in the manner 

 which has caused the synonym P. alatum to be given to the type . 

 In the hypovalve there are two minute spines on the posterior 

 edge, and the longitudinal furrow is strictly defined. In the 

 epivalve the plates are somewhat different in dorsal view and in 

 end view. The three plates in a series resembling a Christmas 

 ciacker are really exactly apical and neither dorsal nor ventral. 

 In a cell of lat. 52 p. the three together measured 40 ^ long 

 (12 +■ 16 + 12), lat. max. 8 M .. 



Peridinium , granulosum mihi. (PI. xliii., f. 1, 2). 



Long. 49-76, lat. 53-76, crass. 63 ^ 



Sydney Water Supply (66, 100); Botanic Gardens (22); 

 Botany (109) ; Auburn (140) ; Fairfield (143) ; Brisbane. 



Syn. Peridinium tabulatum var. granulosum Playf., op. cit., 

 p. 542, PI. lv., f. 1-4. First found in the Sydney City water 

 and since noted from several other localities. The arrangement 

 of plates in the end view of the epivalve shows that it belongs 

 to the P. cinctum group, but it has quite a number of distinct 

 characteristics of its own. In size it is only equalled by P. tabu- 

 latum v. meandrieum Lauterborn; the membrane is not areolate 

 but granulate, sometimes finely and faintly, sometimes coarsely 

 and distinctly, either in lines or scattered irregularly. There 

 is an apical pit in the epivalve connected by a groove with the 

 rhomboidal plate and generally bordered by two minute spines, 

 two are present also at the back of the hypovalve. In this it 

 resembles P. bipea Stein . There is a curious twisted appearance 

 in the hypovalve, the intercalated grooves between the equatorial 



