Lower Silurian.} PALiEONTOLOGY OF VICTORIA. [Graptolites. 



D. pristis (His. sp.), but is easily distinguished by the short, square 

 cells, set at right nnxjles to the axis, instead of the narrow, very 

 oblique ones of that species. The only Graptolite making any 

 apjiroach in the form and direction of the denticles is the bicornis 

 of Hall, which, however, is distinguished by the strong lunate 

 process to the base, from which it derives its name — the base of the 

 present species being a simple point, as in the D. pristis. There is 

 also in most of ^Irs. Hall's figures a perceptible obliquity in the 

 denticles, Avhich so admirable an artist could not have designed for 

 this species ; the bicornute base (so commonly preserved in the 

 D. bicornis) certainly does not appear in ours. Both this and the 

 D. pristis, being of considerable thickness, are occasionally liable 

 to be compressed in a plane at right angles to that usually seen, 

 the two rows of cells being pressed flat against each other, and so 

 producing a form like that figured and described by Hisinger, 

 Portlock, Hall, &c., under the name of Graptolites scalaris. As 

 the numerous specimens under my examination show every stage 

 of the accident, I do not hesitate to recommend the sujjpression of 

 that species. 



In the white, soft Llandeilo flags of (B" 67) section 24, parish 

 of Bulla ; B" G6 ; black slates, Didic River, Gippsland. 



Explanation of Figures. 



Plate I. — Fig. 7, ordinary specimen, uatnr.al size, showing the square notches of the 

 rectangular cells, with an unusual prolongation of the axis. Fig. 7a, magnified yiew of a 

 portion of a curious specimen, in which, apparently by an oblique upward compression of the 

 cells, the lateral notches appear closed. 



Plate I., Fio. 8. 



DIPLOGRAPSUS (CLIMACOGRAPTUS) BICORNIS (Hall). 



Description. — General characters of D. rectangxdaris (McCoy), but the base 

 extended into two oblique horn-like sj)ines. 



Keference.— (Hall), Pal. N. Y., vol. i, t. 73, figs. 2a and b. 



Professor Hall proposes a new genus Climacngrnptus for species 

 like this and the last, having two rows of cells and general 

 character of my Diplograpsus, but the cells not oblique, seeming 



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