626 SOME SYDNEY DESMIDS, 



gulares, angulis inflatis rotundatis, processibus singulis munitis, 

 lateribus levissime convexis, prope latera processibus 6 concen- 

 trice ordinatis, ad angulos versus processibus binis. Membrana 

 subtiliter punctata. 



Long. 55; lat. c.proc. 57/x, s.proc. 48. 



Centennial Park, Sydney Water-supply (22, 42). 



Forma spinosa, n.f. 

 Forma paullo minor, spiculis tenuibus ubique in vicem pro- 

 cessuum instructis. 

 Lat. corp. circ. 42/x. 

 Cum priori. 



St. corniculatum Lund, var. pseudoconnatum. (Platexiii.,fig.l7). 



Forma medio constricta sed sinu vero nullo. Semicellulse 

 latiores paullo depressse, dorso planse, angulis apicalibus rotundatis 

 non mammillatis, aculeis singulis validis munitis, lateribus in medio 

 vix retusis. A vertice semicellulse triangulares, angulis inflatis 

 acuminatis, lateribus sinuatis non (ut in /3 variabile) in medio 

 rectis vel convexis. 



Long. c.ac. 33-42, s.ac. 27-35; lat. isth. 11-13; lat. c.ac. 42-55,. 

 s.ac 30-40; long. ac. 6/x. 



Botany (17), Coogee. 



This form is liable to be mistaken for St, connatum (Lund.) 

 Roy & Biss. /3 Spencer ianum (Mask.) Nord., Frw. Alg.N.Z. T.4, 

 f. 18 (var. rectangulum Roy k Biss., Jap. Desrn. f 12) which it 

 very much resembles. It is distinguished by its larger size, 

 stouter build, and by the diameter of the isthmus which in St. 

 connatum is 6-8/*, in St. corniculatum /3 variabile 12-18/a (16/u 

 Nord.), and in var. pseudoconnatum from 11 upwards Maskell 

 seems to have confounded these species. Nordstedt, I.e. p. 40, 

 remarks : — "The breadth of the isthmus seems much to vary, to 

 judge from the figures in Maskell, 18-8/i; according to the text 

 16-17/*." Those with isthmus about 8/x belong to St. connatum, 

 the rest to St. corniculatum. The life-history of St. corniculatum, 

 as found here, runs as follows : — 



