BY G. I. PLAYFAIR. 



6-49 



I 



DiFFLUGIA BACIM.AKIARUM Pertv. (PI. XXXvii., f.2, 3). 



Length 90-200, breadth 57-84, orif. 34-6 1/x. 



Botany (144); Coogee (58); Lismore (188, 337, 338). 



Syn., D. dcnminata var. haciUifera Playf., Biol. Richm, R., 

 p. 142, PI. viii., f.ll, I give a figure, among others, of Perty's 

 type as found here, cf. Cash, ii., p. 26, f.45. The type itself 

 seems to be .symmetrical, but the specimens met with are quite 

 asymmetrical, except from one point of view. 



Var. AUSTKALis, n.var. (PI. xxxvii , f.4, 5). 



Test broadly ovate, with rounderl dome and convex sides con- 

 verging right down to within a very short distance of the orifice, 

 at which point they diverge suddenly into a slight rim. The 

 test is very often more or less asymmetrical, one side being more 

 inflated than the other, and the tail slanting. Orifice circular, 

 simple. Crown furnished with a tail-like appendage. Test smooth, 

 composed of flat, siliceous plates of irregular shape and size, 

 mixed with fine grains; collar of very small plates of equal size. 



Length 100-120, breadth 57-72, orif. 23-36, tail 12-19, collar 

 6/x high. 



Botany (51, 152); Coogee(58); Lismore (254, 308, 311, 327). 



One of our commonest and most widespread types, with very 

 characteristic shape and, even when 

 asymmetrical, its lines are always the 

 same. It is a finer, broader form than 

 D. hacillariarwm v. eleyans (D. elegans 

 Penard, Faune Rhiz., p. 237, f.l; Cash, 

 I.e., ii., p. 29, f.48), from which it differs 

 also in shape, V)eing ovate and not urceo- 

 late-pyriform, and having a very narrow 

 and distinctive collar. The type here 

 has the same form, with a wider mouth, 

 and the same tendency to be asymmetri- 

 cal. The test is always smooth and plated, 



not rough with coarse flints. One very beautiful test was noted, 

 formed entirely (except the collar) of oval, nebeloid plates (Text 

 fig. 6). One example of var. elegans (Penard) Cash, was r 



47 ' -'^ 



Fig. 6. 

 D iffl iigia haciUariarum 

 var. austraUs, with 

 nebeloid 



