TASMANITES 



15 



Diagnosis. — An adequate description of 

 Tasmanites punctatus, taken here as the 

 type species of the genus, is given by 

 Newton and excerpts from his paper (pp. 

 339, 340, 341) are quoted below : 



When the separated discs are viewed by re- 

 flected light, they appear as more or less 

 circular bodies, somewhat thickened towards 

 the circumference, many of them having their 

 surfaces raised into irregular folds. If mounted 

 in Canada balsam, and viewed by transmitted 

 light, many have the appearance represented 

 in pi. 10, figs. 2, 3, 8, while others exhibit the 

 folds to which allusion has just been made. 

 The more perfect discs are seen to be surrounded 

 by a double contour-line — the optical expression 

 of the fact that these discs are really thick- 

 walled sacs. The saccular character, however, 

 is best seen in transverse sections (figs. 1, 4, 

 5), or when the sac is broken (fig. 8). A 

 closer examination enables one to see that the 

 walls of these sacs are not homogeneous. A 

 view such as fig. 8 shows numerous dots scat- 

 tered over the surface, which become some- 

 what elongated towards the edges of the disc. 

 When examined with a power of about 250 

 diameters, the dots can be resolved into minute 

 circles about 1/3000 of an inch in diameter 

 with a still smaller dot in the centre, as shown 

 in fig. 9. These structures are best seen in 

 the discs of White Coal. It may be thought 

 that these dots are comparable to the granules 

 to be seen upon the surface of some of the 

 macrospores of Flemingites ; but the study of 

 transverse sections shows at once that these 

 dots are not mere surface markings, for they can 

 be distinctly traced as minute lines (tubes?) 

 passing from the outer to the inner surface. These 

 lines are shown in fig. 5, but owing to the section 

 not being quite in the same plane as the lines, 

 they do not appear to extend quite through. 

 In addition to the fine lines, the walls of the 

 sacs exhibit obscure longitudinal markings, 

 which give them a laminated appearance (fig. 

 J ) . 



Neither Mr. Carruthers (Geol. Mag. 1865, 

 p. 432), nor Mr. MacNaughton (Trans. Roy. 

 Soc. Van Dieman's Land, vol. ii, 1855, p. 116), 

 mentions any structure in the walls of these 

 sacs. 



The discs vary in diameter, as stated by 

 both these authors, from about 1/80 to 1/50* 

 of an inch. Mr. MacNaughton speaks of a 

 thin outer coat to these discs, which may be 

 seen when they are ruptured. I have examined 

 all my preparations, both sections and sep- 

 arated discs, in order to distinguish this outer 

 coat, but have been unable to do so. One easily 

 recognizes in transverse sections, such as fig. 1, 

 that the walls of the sacs vary much as regards 

 thickness ; and among the separated sacs which 

 are mounted in balsam some may be seen much 

 more transparent than the rest; but I have 

 failed to see any real difference between the 



* 1/80 and 1/50 of an inch = 317.5 and 508 microns 

 respectively. However, Newton's figure 2 "a large spore" 

 given at 50x would be over 650 microns in diameter. 

 From his figure 5 (250x) the wall is about 2 5 microns 

 thick. In this specimen the wall is about 1/26 of the 

 total diameter. ^ 



thicker and the thinner sacs, or to find them in 

 anything like the relation of an inner and outer 

 coat. 



Prof. Balfour, I believe, considers 



the Tasmanite discs to be closely allied to 

 Flemingites; they differ from them, however, 

 as Mr. Carruthers has pointed out (Geol. Mag. 

 1865), both in structure and size. All the 

 Flemingites macrospores which I have seen 

 have homogeneous walls, and in many of them 

 is seen the triradiate marking, which is so gen- 

 erally present in cryptogamic spores (Prof. 

 Williamson, MacMillan's Mag. March, 1874, 

 p. 409). In none of the Tasmanite sacs have I 

 been able to see this triradiate marking, al- 

 though their structures are so clearly shown 

 that these markings could not fail to be seen 

 if they were present ; and the walls, as we have 

 already seen, have a definite structure. 



The inconvenience of having an 



object without a distinctive name induces me 

 to propose one for the spores (?) found in 

 Tasmanite and Australian White Coal (the 

 two being, as I believe, identical in structure) ; 

 and in order to retain existing titles as far 

 as possible, I would suggest that Prof. Church's 

 name Tasmanite, which is so generally used in 

 reference to the schist as a whole, be retained 

 for this substance, and that the spores (or 

 rather the plant to which they belong) should 

 be called Tasmanites, with the specific title of 

 punctatus, in allusion to their surface-markings. 



The features which are here regarded 

 as generically characteristic of Tasmanites 

 are as follows : 



Symmetry. — Unicentric ; there is evi- 

 dently a center and not an axis of sym- 

 metry as in spores of bonafide plants. 



Shape. — Originally spherical ; except 

 where protected, compression has altered 

 them into disks with a few sporadic 

 rounded folds. 



Si^e. — Ranging from less than 100 

 microns to 600 microns or slightly greater 

 diameter. Forms greatly in excess or 

 much smaller than these dimensions are 

 suspect, because they vary so greatly 

 from the genotype species. 



Ornamentation. — Surface smooth and 

 glistening in reflected light at low magnifi- 

 cation; more detailed examination shows 

 more or less rugosity which may be in 

 part attributable to preservation. More 

 or less regularly spaced punctae varying 

 in number on different forms are visible, 

 but not conspicuous. The forms may be 

 described as essentially lacking in external 

 ornamentation. 



Haptotypic features. — Entirely absent. 

 False conclusions have been drawn either 

 from dififerent forms in association with 

 Tasmanites or from specimens poorly 



