22 Hall : Victorian Graptolites, 



Length of hydrosome, 15 mm. ; breadth, 3 mm. ; thecae, 13 

 in 1 cm., inclined at 40 deg.; apertural mai-gin normal to length 

 of thecae. Virgnla distinct, free for 1.5 mm. Virgella lax, 1 or 

 2 mm. long. Apertural spines of earliest thecae 0.5 mm. An 

 additional spine on the sicular aperture. 



This species has a close resemblance to D. camei, mihi, 

 from New South Wales, but the hydrosome of the latter increases 

 in width continuously. The presence of a free virgula in D. 

 thielei is an additional feature of diagnostic value. 



Climacograptus wellingtonensis, n. sp. 

 (PI. VI., Figs. 2, 3). 



Hydrosome regularly tapering to an acute point. Length, 

 8-10 mm. ; breadth, 0.8 to 1.0 mm. Large specimens may reach 

 a length of 45 mm. and a width of 2 mm., not increasing in 

 width for the last couple of centimeters. Virgula distinct, 

 fi'ee for about 1 mm. In young specimens the free virgula 

 may be longer. Virgella as long as the hydrosome. Thecae, 

 13 in. 10 mm. 



The relative lengths of the free virgula and virgella are held 

 to be of prime importance in distinguishing the species of 

 this group, and the species so distinguished are stated by Lap- 

 worth to have different ranges in time. There are at the same 

 time slight differences in the form of the hydrosomes. The 

 present species approaches the silurian species C. rectangularis 

 McCoy, more closely than any other. 



Climacograptus bicornis, J. Hall. 



A single well-preserved example of this species is present, 

 and is of normal form. 



Cryptograptus tricornis, Canuthers. (PI. VI., Fig. 4). 



Hydrosome of great tenuity, parallel sided, reaching' a length 

 of about 15 mm. and from 1 to 1.5 mm. in breadth. The 

 thecae cannot be distinctly made out nor counted in any of 

 the specimens, but their apertures are distinctly shown by a 

 double series of circular marks, one on each side of the virgula. 



