HARDWICKE'S SCIENCE-GOSSIP. 



J 55 



RECREATIONS IN FOSSIL BOTANY. 



(Sporocarpons and Zygosporites.) 



By James Spencer. 



No. X. 



'/ TRAQUARIA. — This is another very singular 

 J- but most interesting organism. It was described 

 some years ago by Mr. Carruthers, F.R.S., who gave 

 it the name of Traquaria. 



This sporocarpon is about the same in size as S. 

 elegans, the diameter of the central disc being about 

 ^ in. on an average. It has a spherical body, which 

 is furnished with long spine-like appendages, which 

 are covered with muricated projections that in some 

 of the older specimens have been developed into 

 branches. Under a high power, these branches are 

 seen to be round and hollow, like the parent spines, 

 and to be arranged round the spines in verticels, four 

 branches in each verticel. The spines appear to have 

 been very flexible in the young state, but to have 

 become rigid and brittle in the older specimens. A 

 peculiar feature in this organism is that the whole 

 of the body and appendages appear to have been 

 enveloped in a plastic substance. 



The sporocarpon wall is composed of a dark 

 structureless membrane, enclosing the nucleus, a 

 protoplasmic substance, which, in the mature speci- 

 mens, becomes converted into round sphere-like cells. 

 A somewhat warm controversy has taken place 

 concerning the real nature of these organisms. Their 

 original describer maintained that they were of 

 animal origin, and that they belonged to the class 

 Radiolaria. That th'ey have a strong resemblance to 

 some of the latter forms, is unquestionable ; and any 

 microscopist examining them for the first time would 

 be impressed with the idea of their animal nature. 

 Professor W. C. Williamson, F.R.S., however, has 

 always maintained that they were of vegetable origin. 

 "With a view of settling the point, he placed some of 

 these Traquarice in the hands of two of the highest 

 authorities on the subject, Professors Haeckel and 

 Strasburger of Jena, who both declared in favour of 

 their vegetable origin. 



At length the question was finally set at rest by the 

 important discovery in our Halifax material of a 

 Lepidostrobus containing Sporangia, in which some 

 of these Traquaria? were enclosed. 



There were three or four of them in each sporangia 

 thus proving most conclusively that these Traquaria; 

 are true macrospores. In my last paper, at the end 

 of my description of Sporocarpon pachyderma, I said 

 I was inclined to think that those organisms were a 

 young stage of Traquaria. My reasons for this 

 opinion are the following : ist. They both occur in 

 groups'; 2nd. They are both enveloped in the same 

 kind of structureless tissue ; 3rd. The peculiar 

 branching tubes of S. pachydermia, are of the same 

 nature as those at the bases of the spines in Traquaria. 



It is impossible to say whether they really do belong 

 to the same organism or not, until we have obtained 

 further proof. 



Sporocarpon cellulosnm. — This is another seed-like 

 object of which there appear to have been several 

 varieties. It has a spherical body with a central 

 nucleus, which generally contains a number of rather 

 large spore-like cells. The sporocarpon wall is thin 

 and structureless, but it produces externally a number 

 of delicate wing -like expansions. In transverse 

 sections there are generally six of these wings, 

 which are united together at their bases by the same 

 kind of gauze -like tissue. The wings are somewhat 

 irregular in size, but this is probably due to the way 

 in which they happen to have been cut through. 

 In the form of their external coating and wing-like 

 projections these seeds very much resemble what 

 obtains in Sporocarpon astcroides, and yet no two 

 species can be more distinct than these are. In the 

 former organisms, the " wings " and sporocarp are 

 composed of a thin walled parenchyma of very large 

 cells, while in the latter the sporocarp is formed of a 

 very thick walled parenchyma of small cells. This 

 sporocarpon is generally smaller in size than any of 

 those previously described, although a few specimens 

 reach their average size. In consequence of their 

 very delicate structure these sporocarpons are 

 generally found with their " wings " in a more or 

 less dilapidated state, so that although the species is 

 by no means uncommon, yet good specimens are 

 somewhat rare. Here again we have the same 

 tale to tell, already often repeated, of our ignorance 

 as to what these interesting organisms are, whether 

 they are true seeds or spores, and we have not the 

 least clue to the parent plants to which they belonged. 

 Although, judging from what is known about 

 analogous structures, it appears very probable that 

 they are macrospores of some kind of Lepidoden- 

 droid plant. 



Zygosporites. — Among the vast number of spores 

 which are found in our coal-balls, there are none 

 more interesting to the student of fossil botany, than 

 those minute 'organisms which have been described 

 under the name of Zygosporites. There are several 

 varieties of these beautiful spores, and it is impossible 

 for the geologist to examine them long without 

 being struck with their resemblance to those well- 

 known organisms which occur so abundantly in 

 certain chalk flints, and which are familiar to us under 

 the name of Xanthidia. 



So great is the resemblance that upon the first 

 discovery of these spores, and for some time after, we 

 made use of the term Xanthidia as a matter of con- 

 venience in describing our new spores. The fact 

 that no true and undoubted specimens belonging to 

 the Desmidas have as yet been discovered in the 

 coal measures, caused Professor Williamson to 

 incline to the opinion that these spores belonged to 

 some unknown form of Lycopodiaceous fruit, rather 



