Victorian Graptolites. 115 



in the geological collection of the University of Melbourne, and 

 are in a very imperfect state of preservation. 

 Horizon. — Silurian, Melbournian. 



MoNOGRAPTUS PRIODON Bronn. (PI. XVII., Fig. 20). 



Hydrosome straight, rigid, nearly 2.5 mm. wide. Thecae 9 in 

 10 nun., sigmoidally curved and tapering to the aperture. The 

 ■distal third lient back to form a strong hook like portion. Overlap 

 about two-thirds. 



The description is drawn up from a fragment, the only one I 

 have seen. It is in relief, but merely as a cast. The matrix is a 

 whitish, fine-grained micaceous sandstone. 



Locality. — Macclesfield. 



Horizon. — Probably Melbournian. 



Triaenograptus neglectus n. g. et n. sp. (Text Fig. 7). 



Hydrosome probably circular in outline, and slightly concave 

 near the middle, as in some species of Dictyonema. Branches 

 radiating from the centre. These branches give off a pair of lateral 

 branches, one on each side of the main branch. The three branches 

 thus formed produce a trident-like structure, which suggests the 

 generic name. The laterals from one branch usually unite with 

 corresponding laterals given off at the same level l)y a neighbour- 

 ing branch, and then run on as a new single branch. This' in its 

 turn gives off lateral branches, which behave in the same way. 

 Diameter of the type. -^5 cm. Width of branches, 1.5 mm. Inter- 

 spaces or fenestrae, two or three times as long as wide. Thecae, 5 

 •or 6 in 10 mm., only outer and apertural margins visible. Tliey 

 •appear to be straight-sided, and indent the branch for a fifth of 

 its diameter, and appear to be inclined at about 20o, but are so 

 imperfectly shown, that I do not attempt to figure them. 



The symmetrical method of branching is peculiar, and unlike 

 tliat of any other graptolite known to me. Though apparently 

 allied to THcfyonema, it seems worthy of generic rank. 



The present specimen was found stored away in the National 

 Museum, and the only record of its finding is contained in a news- 

 paper cutting pasted on it. This states that a fossil, presumably 

 the present one, was found in the Paving Company's Quarry, 

 Barker's Creek. This can only refer, I think, to a long-deserted 

 •quarry on the right bank of the creek, nearly opposite the late 



