BY G. I. PLAYFAIR. 27 



I have not seen this form in side-view, so cannot determine 

 whether it inclines to the type or to the next variation. It is a 

 little larger than usual, the spines stouter and more regular; the 

 inner third of the spines is the colour of the lorica, the outer 

 part is colourless. 



Var. BISERIATA, n.var. (Fig. 7). 



Lorica depresso-ovalis, ubique rotundata, spinis minutis sparse 

 ornata, spinarum longiorum seriebus binis utrinque ad medium 

 circumcincta. 



Diam. corp. 20; sp. long, ad 6 /x. 



Lismore 241. 



In this species, the type seems to be a form of Tr. volvoGi7ia 

 which has developed the posterior spines of 7V. armata. This 

 variation reproduces the anterior and posterior series of 7V. 

 armata var. duplex. The two rows of spines are, of course, close 

 together, and this is evidence of the fact that the growth of the 

 lorica takes place mainly in the equatorial region. 



Var. iNERMis, n.var. (Pl.iii., f.21). 



Lorica ut in forma typica sed spinis nullis. 



Alt. circa 14-18, lat. 17-22 (rarissime 34) /z. 



Auburn 139, 140; Botany 142, 151; Lismore 236, 237, 241. 



I found this form in my Sydney gatherings (notably Auburn 

 140, ill which it occurs plentifully) before I discovered the mature 

 form at Lismore. The latter is very rare, even where it is to be 

 observed at all. Yar. inerinis is very liable to be overlooked in 

 gatherings. Resting, as it does, always on one end, it appears 

 circular from above, and may be mistaken for Tr. volvocina^ in 

 company with which it is often found. 



Var. OBLONGA, n.var. (PL iii., f.22). 



Lorica ut in var. biseriata, sed spinis nullis. 



Diam., vertice visa, 12; alt., a latere, 8 fj.. 



Guildford 70. Very rare. 



A smooth form of var. biseriata. Although I have seen no 

 intermediate forms, yet there is such a close agreement in the 

 side-view of all these forms, that I must consider them variations 

 of the same species. 



