1 8 MAECHANTITES. 



Genus MARCHANTITES, Brongniart. 

 [Tatleau, p. 12.] 



Yegetative body of laminar form, with apparently dictotomous 

 branches, and agreeing in habit with the recent thalloid ffepatica, 

 as represented by the genus Marchantia. 



Brongniart's term Marohantites is, in the present instance, pre- 

 ferable to Marchantia; the latter would suggest a fossil which 

 might reasonably be regarded as a species of the recent genus ; 

 the former has a wider meaning, and, if used in the broad sense 

 indicated in the above definition, would refer rather to a type 

 of vegetative body than to a special genus. 



1.— Marchantites Zeilleri, sp. nov. 



Type. Specimen in the British Museum. V. 2330. Discovered 

 by Mr. Eufford. PI. I. Kg. 3. 



"Frond" repeatedly divided by forked branching, apparently 

 dichotomous. Average breadth about 3mm. ; the branches have a 

 distinct and fairly broad midrib, and on either side of the central 

 axis are thin and filmy. 



I have named this Wealden species after Professor Zeiller, of 

 Paris, who is one of the authors of the oldest known species of 

 moss, and whose labours in palseobotany have done so much to 

 establish the subject on a more scientific foundation. 



In habit and size this species very closely resembles Marchantia 

 Chenopoda, Linn., from tropical America. No other genus, so far 

 as resemblance in habit is concerned, agrees so nearly with the 

 "Wealden form as Marchantia,, but without trace of either male or 

 female receptacle, or other aids to identification, no great stress 

 should be laid on the comparison. There is the same branching 

 habit and distinct midrib in Leckenby's species, Fucoides erecius.^ 

 In both the midrib is clearly shown by the much darker colour of 

 the median portion of the thalloid impressions ; the thinner lateral 

 parts in the present species appear almost like brown stains on the 

 matrix. A somewhat similar form, but without any striking 

 resemblance, and, indeed, of much smaller size, is figured by Debey 



' Quart. Joum. Geol. Soo. vol. xx. p. 74, pi. xi. fig 3. 



