New Old Hare Fussiti^. 167 



hitherto Ix-eii the usage amongst pahieobotaiiistst to separate the 

 encrusting forms of Lif/iot/uinnuon as Lif/inphi/llum; but as Foslie 

 (whose untimely deatli we have recently had to deplore), showed, ^ 

 that, having regard to the J-eproductive organs of the plants, that 

 method was based on insufKcient ground. From a study of the 

 recent form-s of tlie gi-oup, Foslie included nearly all the species 

 of Tjithnphylluiii in Uthothamnion, the latter genus being defined 

 In- the (l<>\\nwai(l giowtli of the conceptacles into the frond (subgen. 

 E nlithothainiiion . sect. Innatae) or by their superficial character 

 (sect. Evanidae). The present species falls into the first section of 

 the sul)genus mentioned. 



The eonie))ta(les with teti-aspoi'es can be found in the fossil 

 examples by slicing, almost' as easily as in tlie recent forms. In 

 these specimens from the polyzoal rock of the Mallee bores, it is 

 found that the conceptacles are immersed in the thallus, the surface 

 of which is sometimes overarched above the conceptacles. The 

 conceptacles here examined were slightly broken during slicing, so 

 that the true outline of the cavity was not seen. It has already 

 been stated^ that the tetraspores " could be but imperfectly fossil- 

 ised," since they contain very little carbonate of lime. It is, there- 

 fore, particulaily interesting to note that the tetraspores are here 

 present, and preserved as glauconite pseudomorphs of a pale green 

 tint. The example figured shows two of the tetraspores clinging to 

 the inner wall of one of the conceptacles, whilst another is seen in 

 an adjoining cavity. These tetraspores are ovoid, and pointed at 

 the base of attachment. The pseudomorphic change into glauconite 

 shown In- tliese fossil bodies is more easily understood when we 

 compare them with the sarcode bodies of Foraminifera replaced bv 

 the same substance, foi- 1 am inclined to believe that the glauconiti- 

 sation of foi-aniinifera takes place as a reactionary product of the 

 protoplasm, and not as a nieie infilling of the dead shells, in which 

 case we should most i)r(>l)nbly get a concentric structure developed 

 in the glauconite. This assumption can, of course, only be proved 

 by detailed observation and chemical experiment. 



In Lifhothamnion nummnliticum* the cell structure i.'> quadrate 

 and smaller than in //. rninosissimum, to which we refer nearly all 

 the present examples. The specific standing of the latter is further 



1. Seward. Fossil Plants, vol. i.. Caiiibridge, ISns, i> 186. 



2. Foslie. Op. supra {'it., p. 5, et seq. 



3. See Waters, A. W., on " Fossil Lithothamnia". Mem. Lit. and I'liil. Soc .Manchester, vol. 

 1874, p. '248. This pai)er gives a useful resume of the ociuireuces of the fossil LithothaiuTiia 

 roek-formini; aireuts (pp. •.;44-2.in). 



4. IJthotlMuiniam iriiuinndhirinii. r,\\n\h^-\. \\<\\M\<\\.\i\>A\..-r. .\k. Wiss., vol. xi. (1), 1 

 p. 37, pi. i, f\%. i/ie. 



