]68 Proceedings of the Royal Society of Victoria. 



mm. and scarcely visible except under the lens. Thecae 11 or 

 12 in 10 mm. slightly expanding towards the aperture, over- 

 lapping for one half their length, two and a half times as long as 

 broad ; apertural margin slightly concave, inclined at an angle 

 of about 80° to the axis, so that the aperture looks slightly 

 inwards ; outer margin gently concave and inclined at an angle 

 of 25°. 



In one case the virgula, at a distance of 4 mm. from the sicula, 

 appears to terminate in a pear-shaped vesicle about 0.7 mm. in 

 length, being attached to its smaller end. As, however, the 

 virgula is not exposed the whole way, the connection is not 

 certain and my attempts to clear it have not been successful. 



Named as a tribute to the memory of the late Norman Taylor 

 of the Victorian Geological Survey. 



Tetpagraptus, Salter, 1863. 



Tetragraptus decipiens, n. sp. 



(PL XVII., Figs. 13-15; PL XVIII., Fi-s. 16-19). 



Tetragraptus quadribrachiatus, Pritchard {iion J. Hall). Proc. 

 Roy. Soc. Vic, N.S. vii., 1895, p. 30. 



Form stout, branches arising close to the sicula, apparently 

 from the second and third thecae, and from 0-5 to 1 mm. broad. 

 Thecae slightly expanding, overlapping for about one half their 

 length ; apertural margin concave, set at an angle of from 95 

 to 100° to the axis of the branch ; outer margin with a slight 

 concave curvative which gently increases near the aperture ; 

 inclined at first at an angle of about 10° to the branch and near 

 the aperture of about 30°. Virgula shown as a tine line, often 

 about 7 mm. in length. 



Figures are given showing the apparent variation produced 

 by the polypary being embedded in different positions. Fig. 13, 

 wliich represents a common method of preservation of young 

 specimens, shows that the angle of divergence of the branches 

 is less than 180°. With increase in size this position becomes 

 less common, and a regular cross is displayed. In this latter 

 case the thecae and sicula are naturally not well shown and the 

 likeness to similarly preserved specimens of T. quadribrachiatus 



