BOT.-VOL. II.l HUS—PORPHYRA. 191 



With the material at the disposal of the author, he has 

 been able to distinguish between four types of division of 

 the reproductive bodies, the differentiation into types being 

 based upon the number of antherozoids and carpospores 

 produced. The first is the P<?r//i!yrrt/^;ybr«/f« type. Here 

 thirty-two carpospores are produced, the sporocarp under- 

 going first a cruciate division, followed by a parallel division 

 in each of the segments, which is again followed by a cru- 

 ciate division of each segment. If we represent a vegeta- 

 tive cell by a cube, and indicate the two horizontal lines 

 respectively as a and b, and the perpendicular as c, we 



can, by the aid of the formula 32 I — , — , — j readily form 



a diagram such as is represented in fig. 25, which shows 

 the manner of division. 



The antherozoids contained in each antheridium number, 

 in the P. perforata type, 128, and are formed by alternat- 

 ing parallel and cruciate divisions, the first division of the 

 antheridium being parallel to the surface of the frond. ^ The 

 manner of division may be represented by the formula 



128 (i^, ^^, ^\ (fig. 28). To this type belong P. 



\ 4 4 ^ / 



-perforata, P. perforata f . lanceolata, P. perforata f . segre- 



gata and P. nereocystis. 



The second is the P. leucosticta type. Here eight carpo- 

 spores arise from a cruciate division of the sporocarp- 

 mother-cell, followed by a parallel division of the four 

 segments. This may be represented by the formula 



8 (f 4- ^) (%. a4). 



The antherozoids contained in each antheridium of the 

 fronds of species belonging to the P. leucosticta type num- 

 ber sixty-four. They are formed by first a parallel division 

 of the antheridium, followed by a cruciate division, after 

 which a second parallel and a second cruciate division take 



1 It must be remembered that an antheridium is but one-fourth as large as a sporo- 

 carp, the first division of the antheridium-mother-cell, which corresponds to both a 

 vegetative cell and a sporocarp-mother-cell, being vegetative and cruciate. 



