304 Proceedings of the Royal Society of Victoria. 



Ppimitia halli, sp. nov. (PL XIV., Figs. 2a-c). 



Description. — Carapace elongate and sub-rhomboidal as Been 

 from the side, with both the anterior and posterior angles, dor- 

 sal and ventral, rather sharply truncated ; dorsal border 

 straight, ventral slightly concave. Dorsal furrow sub-triangular. 

 Dorsal margin having a narrow flange which is continued partly 

 along the antero- and postero-dorsal margins. Edge view com- 

 pressed ovate, thickest in the anterior third. Anterior end 

 compressed, posterior compressed and somewhat bluntly 

 rounded. End view sub-cordate. Tlie right valve somewhat 

 smaller than the left. Surface somewhat uneven or sparsely 

 pitted. 



Dimensions. — Length of compace, 1.08 mm. ; height, .43 

 mm. ; thickness, .35 mm. 



Observations. — The above species is apparently distinct from 

 any hitherto known forms of Primitia. The only species which 

 is at all comparable with ours is P. furcata Jones and HolP, 

 but this is much higher posteriorly, whilst anteriorly it tapers 

 from the curved ventral to the dorsal margin, and the hinder 

 portion of the carapace is considerably thicker and blunt- ended. 



This species may very appropriately be associated with the 

 name of Mr. T. S. Hall, M.A., wdth whom I had the pleasure 

 of first visiting the Cave Hill quarry, and on which occasion 

 we obtained material fairly rich in ostracoda. 



Locality and Horizon. — Cave Hill, Lilydale. Silurian (Yerin- 

 gian). 



Primitia elongata, Krause, var. nuda, Jones. (PI. XIV., 

 Figs. 3a-c). 



Primitia elongata, Krause, var. nuda, Jones, 1893. Quart. 

 Journ. Geol. Soc, vol. xlix., p. 298, pi. xiii., fig. 6. 



Observations. — Our examples agree exactly with Prof. Jones' 

 figure with the exception that the dorsal sulcus is represented 

 by a well-defined depression. Both the type and the variety 

 originally came from the Ordovician, of Scandinavia and Scot- 

 land respectively. 



1 Ann. Mag. Nat. Hist., ser. 5, vol xvii., 1886, p. 413, pi. .\iv., figs. 15a, b. 



