THE AMERICAN NATURALIST [Vol. XLIII 



The base of the stipe was but slightly larger than the 

 portion above and gave off a large number of filamentous 

 processes, some of which seem to have pressed against 

 the substratum, while others apparently connected with 

 the filaments around the base. Notwithstanding its small 

 size this specimen had a well-developed stipe about a 

 dozen layers of cells in thickness. The internal cells are 

 considerably elongated, though not, as far as can be seen 

 by focusing, differentiated into a pithweb. The lamina 

 was already several cells in thickness even at the edge. 

 Since it was but little frayed, it hardly seems possible 

 that there could have been any remnant of the one-lay- 

 ered lamina which had not been transformed into the 

 many-layered adult blade. Id this respect Lessoniopsis 

 would stand at the opposite extreme from Cymathere, in 

 which a large portion of the embryonic lamina is not 

 changed, but continues to grow and persists until the 

 plant is more than 20 cm. long. 



The next larger specimen (Fig. 4) measures 2.3 mm., 

 but its true length must have been about 5 mm., for it is 

 sharply truncated a little above the base of the lamina. 

 The holdfast of this specimen was enlarged to form a 

 fairly well developed primitive disc, the base of which 

 was, as in the first specimen, more or less imbedded in a 

 mass of filaments apparently belonging to the kelp. The 

 lamina was much thicker and the spots were seen to be 

 in two layers, one on each side, just beneath the epi- 

 dermis. In the smaller specimen (Fig. 3), where one 

 spot overlapped another, the two layers could also be 

 made out, but the difference in focus was so slight as to 

 make it appear that they lay in contact, indicating that 

 the lamina was four cells in thickness. In the larger 

 specimen they were separated by a considerable interval 

 which indicated a decided development of the pithweb 

 and cortex. Toward the extremity of the lamina the pig- 

 mented spots were very dark and most of them were con- 

 siderably elongated. They still consisted, however, for 

 the most part, of single cells. Farther back in the tran- 

 sitional region, they were lighter in color, round and more 



