TRAQUAIRIA, SPOROCARPON. 



183 



to be macrospores of Lepidodendreae, Radiolariae, and zygotes of Desmi- 

 dieae. It appears to me, and to Strasburger * also, that if they can be 

 compared with anything, it is first of all with the massulae of Azolla, or 

 with the 'sporocarps which contain them ; and though this comparison 

 must be distinctly proposed as a possibility only, we may nevertheless 

 consider these remains in this place, since none more appropriate has been 

 found. 



Sporocarpon compactum a is a small spheroidal body scarcely visible 

 to the unaided eye, and consists of a stout solid case of very peculiar 

 structure inclosing an inner cavity, which contains a variable number of 

 round smooth-walled cells. Outside and 

 between these cells is a brown and formless 

 mass, but they are also not unfrequently 

 clothed with a thin folded membrane. The 

 case is itself composed of a homogeneous 

 structureless firm inner leaf with a double 

 contour-line, and on this leaf and occupy- 

 ing the position of a compact palisade-tissue 

 are hollow cylindrical bodies, which grow 

 narrower and cone-shaped towards the apex, 

 or in some cases are prolonged into conical 

 hairs, and form a closed rind ; no contents 

 are discoverable in these bodies, and their 

 wall is formed of the same substance as 

 the leaf on which they rest, but is of 

 slighter consistence. Williamson has em- 

 ployed the sculpturing of the outer case 

 to distinguish several other species of 

 the genus ; in his Sporocarpon elegans (Fig. 18, B] the hollow cy- 

 linders which form the rind have the shape of an hour-glass and leave 

 empty spaces or cell-like gaps between them, but are in immediate 

 contact at base and apex all the way round. Some of them also are 

 prolonged into long conical -hairs. Williamson 4 supposes that this was 

 originally the case with all of them, but that in the greater number the 

 hairs have been broken off. Another form resembling Sporocarpon com- 

 pactum without hairs is named by Williamson 5 S. tubulatum. In a few other 

 forms also placed in the group, S. pachyderma 6 , S. asteroides 7 , and S. 

 ornatum 8 , the layer of cylindrical bodies is replaced by a thick frothy mass 



FIG. 18. A large receptacle of Traquairia, 

 Carr. , inclosing numerous spores, and covered 

 on the outside with hollow tubular processes 

 which give rise to lateral ramifications. B 

 fragment of the outer wall of Sporocarpon 

 elegans, Will., with the hollow conical ap- 

 pendages. Both after \Vi"i? ms on 3. 



1 Williamson (1), X, p. 515. 2 Williamson (1), ix, t. 24, f. 760:, and X, t. 17, f. 31. 



;1 Williamson (1), X. 4 Williamson (1), X, p. 507. 5 Williamson (1), IX, t. 24, f. 78. 



6 Williamson (1), X, t. 17, ff. 35, 36. 7 Williamson (1), x, I. 17, f. 38, and t. 21, f. 89. 



8 Williamson (1), X, t. 18, f. 39. 



