T. U. BUFFHAM ON ANTHERIUIA. 



thickness of the membranons frond itself is about 40 /la. Where 

 tlie anthoridial h\yers occui* the total thickness is then about 

 80 /I, of which each layer occupies about SO ^(, and the middle 

 line of cells is then reduced to 25 fx. The nuile cells are closely 

 set and well covered with the usual gelatinous accompaniment 

 (Fig. 21). (Swanage, Aug. 1890.) 



The genus Pt7t»vr/a undoubtedly stands near to Xitoj^hi/llum^ 

 and we naturally tind a resemblance in their antheridia. In 

 D. alata Lamour. the nuile organs arc found in minute leaflets 

 arising from the apices of the plant, and, especially, in groups 

 from the axils. These leaflets are about 1 mm. long by 'b-'7 

 wide (Fig. *J-). A transverse section shows layers to practi- 

 cally cover both surfaces (Fig. 23). The gelatinous covering is 

 not so great (Fig. 24) as in the preceding species. (First 

 detected by rae on a dried specimen collected by Mr. Neeve at 

 Deal, Nov. 1883, and sent me in 1890. Figui-es are drawn from 

 a fresh specimen collected also at Deal, Nov. 1891. Mr. Batters 

 found it at Berwick, Oct. 1889.) 



In D. ruscifolia Lamour. the antheridia arc found on all the 

 leaflets of the plant, and to the naked eye appear as interrupted 

 lines lying each side of the midrib. A low power sulliccs to 

 show that the general longitudinal arrangement is made up of 

 minute irregular spots which are frequently elongated obliquely 

 by extending between the lateral veins (Fig. 25). Here a trans- 

 verse section of a leaflet through the lamina bearing two spots 

 on each face gives very irregular outlines of the exterior of the 

 spots, with a thickness through all of about 70 fx (Fig. 2(3). 

 The male cells are much slenderer (Fig. 27) than those of the 

 preceding species. (Swanage, Aug. 1890.) 



The most conspicuous antheridia known to me are those of 

 HydwlapatJitmi sangnineuni Stackh. (Delessena samjuinca 

 Lamour.) Like the cystocarps and leaflets bearing the tetras- 

 pores the male leaflets spring from the midrib of the " leaves " 

 when the beautiful lamina has nearly disappeared, leaving only 

 defaced and ragged remnants. A tuft of the natural size is 

 shown in Fig. 28. Some leaflets reach a length of 6 mm. 

 They are white, and are covered on both sides — with the excep- 

 tion of a border of a few cells wide — by a imiform layer of 

 gelatine in which the male cells are set (Fig. 29). The leaflet 

 is thickened along the middle as seen in a transverse section. 



