AND ELATERS OF MARCHANTIA POLYMORPHA. 109 



coats, while Gottsche says that Pellia and Blasia have a single-coated spore, and Fim- 

 briaria and Preissia apparently have two coats. I believe that this point can only be 

 determined with certainty when the spores are germinating, and observation of this pro- 

 cess leads me to the result that the membrane is simple in Marchantia polymorpha. 



In conclusion, I cannot refrain from directing attention to the striking circumstance, 

 that I met with no nuclei throughout the whole course of development. Mohl, in his 

 essay on Anthoceros Icevis, describes a series of phenomena connected with the appearance 

 of nuclei, of which I saw nothing in Marchantia ; neither did I see any nuclei during the 

 development of the spores of Sphcerocarpus terrestris, which I partially traced last spring. 

 Sometimes the globular bodies in the yellow protoplasm present appearances which might 

 be mistaken for nuclei, but careful investigation always led me to believe that these 

 appearances were deceptive; and as I obtained clear and well-defined views of all the 

 various stages, with fully sufficient magnifying powers to see nuclei if present, I am com- 

 pelled to deny their existence here. 



The main point, however, to which I wish to direct attention in this paper, is the 

 singular manner in which the subdivisions of the cells take place, in order to produce the 

 very dissimilar forms of long filiform elaters and spherical spores, from a tissue originally 

 homogeneous. 



London, Nov. 10th, 1849. 



DESCRIPTION OE THE PLATE. 

 Tab. XI. 



Fig. 1. A pistillidium containing the nascent sporangium at the bottom. 



Fig. 2. More advanced sporangium a, enclosed in the membranous involucel, b, formed from the pistil- 

 lidium. c. The outer involucre laid open. 



Fig. 3. Portion of the wall of the sporangium 2 a, formed of cubical cells filled with chlorophyll. 



Fig. 4. a. Two ripe capsules with their burst proper involucels, displayed by laying open the outer invo- 

 lucre ; b and c. bursting sporangia. 



Fig. 5. a. Portion of the elastic wall of the capsules 4, b and c. b. Two cells from the same, one with a 

 spiral fibre, the other annular. 



Fig. 6. Contents of the sporangium 2 a, consisting of broad and slender tubes. 



Fig. 7- a. One of the broad tubes with the contents coagulated; b. one of the narow ones (elater). 



Fig. 8. More advanced condition, with cross lines indicating the formation of septa : a. coagulated in 

 water ; b. by iodine. 



Fig. 9. More advanced stage : a. fresh ; b. with iodine. 



Fig. 10. Later stage ; the protoplasm becoming thickened in some cases. Vertical septa forming in some 

 cells : a. in water ; b. with iodine. 



Fig. 1 1 . Single and double rows of cells formed from the tubes, 7 «. 



Fig. 12. a. Rows of parent-cells; b. young elater containing starch-granules; c. part of the same with 

 iodine. 



Fig. 13. Parent-cells in which the contents are beginning to produce the spores; the single one a free 

 parent-cell in which the portions exhibit a membrane. 

 VOL. XXI. Q 



