BY G. I. PLAYFAIR. 1 63 



iiiterdum productis bi-(rarius tri-)deiitati8. In quaque semiceilula 

 verticilli 13-16, dentibus magnis, validis, patentibus 10 instructi; 

 dentibus verticilli basalis in margine inferiore denticulis sinsfulis 

 ornatis. 



Long.c. proc. 450, 480, 588; lat. c. dent. 50, 57, 50/x. 



Botany. 



This form lies between Trip, verticillatum Bail.,* superhmn 

 (Mask.) Nord., and Trip, gracilef hidentatum f. intermedia Nord. 

 Looked upon as an immature form, it could develop into the 

 former by the teeth becoming bifid verrucae, or into the latter 

 by their lengthening out into aculei. No tendency of the sort 

 has been noticed, however, in any of the specimens that I have 

 observed. 



Trip, gracile Bail., *bilobatum Turn., Alg. E. India, p.26, 1\2, 

 f.4. C/.'West (Desm. N. Amer. T.13, f. 10-13) especially the 

 end views. 



The specimens noted had 10 teeth to the verticil and 17 

 verticils to the semicell. Also the apices were 4-lobed, each lobe 

 bidentate. I liave noticed in other varieties of Triploceras the 

 ''two intervening spines" mentioned by Turner, I.e., in bilobed 

 apices. It seems probable that such a form is immature, and 

 that the two spines on each side develop into bidentate lobes, 

 thus forming a 4-lobed apex. {Cf. T.ii.,f 15.) 



Long. 444,530; lat c.ac. 34, 33/x. 



Botany. 



Trip, gracile Bail., ^aculeatum Nord., Fr.Alg.N.Z.,T.7, f.13-14, 

 forma austkalica, n.f. (T.ii. f. 14-15). 



A forma novizelandica differt cellulis minoribus, semicell uHs 

 magis attenuatis, verticillis 8-11 in quaque semiceilula. 



Long. cell. 276, 300, 430; lat.c.ac ad bas. 24, 36, 50; lat.s.ac. 

 20, 18; lat. sub. lob. ap. 11, 11/x. 



Botany, Centennial Park. 



*Fr. Alg. N. Z. T.7, f.3. 

 •H.c. T.7, f. 17. 



