3 



THALLOPHYTES, BRYINAE. 



differ from one another according as they proceed from the members or 

 from the joints. Their whorls are closely crowded together, more closely 

 in the joints than in the members ; the lumina of all their ramifications 

 traverse the thick membrane of the central tube like narrow pipes and 

 communicate with its cavity. The whorls which are upon the joints consist 

 of short branches of simple cylindrical form directed obliquely upwards, 

 and becoming successively shorter from below upwards. At the apex of 



each branch is a broad scar, on 



lUMMii-MMHW^ which one of the branched hairs 



once stood which, as we have 

 already explained, are attached 

 to the younger parts of the thal- 

 lus. These hairs are developed 

 only on the whorls of branches 

 which belong to the joints. 



Each branch of a whorl, 

 standing out at right angles to 

 the thallus, ends inside the cal- 

 cified members in a bladder-like 

 swelling, and bears above this a 

 large ovoid sporangium on a 

 small and very short stalk. Four 

 to six branches of the second 

 order, of exactly the same shape 

 as those of the first, spring from 

 the apical surface of the primary 

 branch and surround the sporan- 

 gium. Their bladder-like ex- 

 tremities unite above the sporan- 

 gium, and laterally with those of 

 the adjoining system of lateral 

 branches, and become pretty 

 firmly attached to one another. 

 In this way a continuous cor- 

 tical layer is formed, which when seen from without appears to consist 

 merely of single separate cells. The broad gap which remains beneath this 

 rind between the filamentous members of the first and second order is filled 

 with a mucilage formed from the swelling up of the outer layer of their 

 membranes, and it is this only which being thoroughly calcified becomes 

 thereby hard and brittle. The inner membranous layers which adjoin the 

 lumen and are not disorganised continue entirely free from lime. Bounded 

 by these membranes, the cell-lumina of the verticillate branches and of the 

 sporangia are seen as cavities and canals full of protoplasm traversing the 



FIG. 2. Cymopplia barbata, from specimens in spirit in the 

 collection at Gottingen, which were obtained by Askenasy in 

 Grand Canary. A showing the habit of a small piece of the 

 plant. />' longitudinal section of part of the same with one of the 

 non-calcified places of articulation of the thallus. At this 

 place the lateral members of the whorl are not branched, and 

 terminate in a scar which once bore one of the branched hairs 

 of the tuft ; the hairs forming the normal terminal tuft are still 

 to be seen in A attached to the youngest parts of the thallus. 

 Where the members are calcified, all the branches of a whorl 

 bear a terminal sporangium and from four to six peripheral 

 branches of the second order, which swell into the shape of 

 a bladder at the apex. These bladder-like swellings, connected 

 with one another by their sides and not calcified, form a regular 

 outer rind, which collapses in drying and is therefore wanting 

 in fossil specimens of Pplytrypa. The limits within which the 

 calcification is confined is indicated by dark shading. A slightly 

 magnified. 



