•I 

 448 T. 8. Hall — OrapfolUe Rocks, Victoria, Australia. 



Remarks on some of the Forms, with Descriptions of 



New Species. 



Monograptus, sp. (PI. XX TI, Fig. 1.) 

 The specimen figured shows the characters of the genus, but is too 

 imperfect for specific description, and the figure is merely given as 

 evidence of the occurrence of tlie genus in our beds. 



Locality. — Keilor, from the locality where Aplia first found 

 graptolites. 



Didymograptus gracilis, Tornquist. (PI. XXII, Fig. 2.) 

 Acta Univ. Lund, vol. xxvi, pt. 2, iv, p. 17, pi. i, figs. 9-12. 



Hydrosorae slender. Sicula about 1-3 mm. long and \ery narrow, 

 with a very delicate virgula, which is traceable for about 0*7 mm. 

 Branches extending at 180° and apparently arising at very different 

 levels from the sicula, the left side of which projects as an acute 

 tooth. The left branch is given ofi" from about its middle, the right 

 branch appearing to rise at the level of the aperture. Dorsal edge 

 of ihe branches convexly swollen opposite the middle of each theca. 

 Thecas about seven in 10 mm.; slender; outer edge slightly concave, 

 apertural edge straight and facing somewhat inwards, the two edges 

 forming an acute denticle. 



Tornquist says that he had an example showing the hair-like 

 virgula, but that he was subsequently unable to find it.^ It is 

 clearly visible in the figured specimen. Breadth of branch about 

 3 mm. ; width of thecse at aperture about the same. 



Locality. — Bendigo ; exact locality unknown. 



Leptograptus antiquus, T. S. Hall. (PI. XXII, Figs. 3, 4.) 



Locality. — Lancefield. 



Teiragraptus projectus, n.sp. (PI. XXII, Figs. 5, 6.) 



Primaries in a straight line, about 1 mm, long. Secondaries 

 diverging at an angle of 90° from each other, rigid, narrow, about 

 1-5 mm. broad, and may be more than 6 cm. long. Central disc 

 oblong, with straight sides, slightly curving outwai'ds at the angles 

 to embrace the secondary branches. Length parallel to the direction 

 of the primary branches, 7 mm. ; breadth, 5 mm, Sicula not visible. 

 Thecae eight in 1 cm. ; short ; slightly expanding ; apertural margin 

 slightly concave, forming an angle of about 105° ; outer margin 

 concave, inclined at 50° to 55°. Amount of overlap not clearly 

 shown in the only specimen found, and cannot be traced further than 

 is shown in the enlarged figure (6), 



The narrowness of the secondary bi'anches and the prominent 

 thecas distinguish the species from all others to which I can find 

 reference. 



Locality. — A single specimen, both sides preserved, from the slate 

 quarries five miles west of Gisborne, associated with the large form 

 of Didymograptus caduceiis, Tetragraptns serra, Diplograptas, sp., 

 Climacograptus, sp., and apparently Phyllograptus typus. 



1 Loc. cit., p. 17, footnote. 



