106 T. S. Hall: 



DiDYIMOGRAPTUS LATENS n. Sp. (PI. XVII., Fig. 5). 



IlyJnjsonie small. The branches curve towards one another 

 dorsally, and become horizontal about the region of the fourth 

 theca, the gentle curvature of the dorsal edge of the branch being 

 very characteristic. Sicula broad and stout, about 1.5 mm. long, 

 and slightly more across the aperture. Tliecae 10 in 1 cm., very 

 slightly expanding, i^^clined at 25°, ovei'lapping half their length. 

 Apertural edge normal to the thecal axis. 



I have previously referred to this species as B. aff. decens 

 Tqt.' ; but the form of the sicula is different. It differs similarly from 

 D. suecicus, Tullb. 



Locality. — The type is from Diamond Hill, Bendigo, about 200 

 yards east of State school. 



Horizon. — Upper and Middle Bendigonian. It is common, and 

 apparently always small, at many localities. 



DiDYMOfiKAPTUs PROCUMBENS n. sp. (PI. XVII. Figs. 6 and 7). 



Branches arising at right angles to the sicula, and then almost 

 imperceptibly reflexed. Breadth at first theca 0.75 mm. ; at 1 cm., 

 1.5 mm.; at 2 cm., 1.75 mm. Sicula 2 mm. long, 0.5 mm. broad, 

 its aperture almost hidden by the first thecae. Thecae narrow, 

 straight-sided, 8 in 1 cm., inclined at about 2()o near the sicula, 

 increasing to a little over 30o at 1.5 cm. Apertural margin from 

 lOOo to 120O. 



In the Bendigo and Lower Castlemaine series the size of the 

 hydrosome never seems to be more than 1 cm. in length, whereas 

 in the slates of Victoria Gully, Castlemaine, just after the dis- 

 appearance of Fhyllograptus fj/pus, a form occurs, which I regard' 

 as this species, which reaches a length of 4 cm. 



Locality/ of type. — Diamond Hill, Bendigo. 



Horizon. — Bendigonian to Middle Castlemainian. 



DlDYMOCRAPTIS ADAMANTINUS U. sp. (PI. XVII., Fig. 8). 



liiiinches about 1.5 cm. huig, and lather slendei- ; widtli about 

 0.7 itim. near the proximal end, increasing to 1 nmi. at al)out 1 cm. 

 from origin. Branches diverging at 15()o to 160^, and almost 

 straight. Thecae 10 or 11 in 1 cm., slightly expanding, overlap- 



1. Geol. Mas., 1SS!>- 



