174 Proceedings of the Royal Society oj Victoria. 



convex, outer margin sliglitly concave. Attempts made to clear 

 the specimen not being successful I thought it advisable not 

 to endanger it. I have very little doubt that the generic 

 reference is correct, though the occurrence of the form in the 

 Lancefield rocks must be very rare. The specimen was collected 

 by Mr. G. Sweet. 



Dictyonema, J. Hall, 1852. 



DiCTYONRMA MACGILLIVRAYI, T. S. Hall. 

 (PL XVIIL, Fig. 27). 



Dictyonetna grande, T. S. Hall {}io>i Nicholson). Proc. Roy. 

 Soc. Vic, N.S. iv., 1892, p. 7, pi. i., ii.; id., Pritchard, lb., vii., 

 1895, p. 28. 



Dictyonema macgillivrayi, T. S. Hall. lb., x., 1897, p. 15. 



The thecae have been described by ]\Ir. Pritchard and owing 

 to his kindness I am able to give a figure of them from his 

 specimen. Fragments of the species are not uncommon. 



Dictyonema pulchellum, n. sp. 

 (PI. XVIIL, Fig. 28-30). 



Hydrosome circular, about 15 mm. in diameter; branching 

 dichotomously from the base, at fairly regular intervals. Kadial 

 branches about 1 mm. broad. Connecting branches at right 

 angles to these, about 1 mm. apart and about 0*2 mm. broad, 

 expanding at the point of junction with the radial branches. 

 Thecae with slightly concave apertural margin at right angles 

 to the branch ; outer margin straight, forming an angle of 

 25°-30° with the axis of the branch ; probably about 7 in 10 mm. 



This pretty little form is represented by four examples in the 

 collection of Mr. G. B. Pritchard, and are all on one small slab. 

 One specimen has been compressed laterally, so that the hydro- 

 some was apparently cup shaped, and in this example the thecae 

 are visible near the base. In none of the other examples can I 

 detect any signs of thecae which are most likely embedded at 

 right angles to the bedding plane. 



