THE MARINE ALG.E OF NEW ENGLAND. 19 



female by the brii;:liter color of the tip.s ^vhiL•ll bear the couceptaeles. 

 A section through the conceptacles of the male plant, as in PI. IX, Fig. 13, 

 shows a number of branching filaments which line the interior of the 

 conceptacle. Attached to the lilaments are oval bodies, the antheridia. 

 The antheiidia contain the antherozoids, which are ovate and provided 

 with two eilia attached at the side. Usually about day-break the an- 

 theridia discharge then- antherozoids, which then swim about in the water 

 until they reach the female plant. A section through the tip of a 

 female plant shows a number of couceptaeles similar in shape to those 

 of the male plaut. On the walls of the conceptacle there are i)araphyses, 

 and scattered among them are the oogonia, as shown in PI. IX, Fig. 1. 

 The oogonia are oval and scfjted on broad short pedicels. In Fucus 

 resiculosm the contents of the oogonia divide into eight oosphercs, which 

 are at first angular, but afterwards become spherical. The oogonia be- 

 come free from their attachments, and the wall, which is really double, 

 ruptures, and the oosphercs escape into the water. In this condition 

 they are merely spheres of protoplasm. The antheridia then collect 

 around the oosphercs in large numbers, and the mass begins to ro- 

 tate. The rotation continues for a short time, and when it ceases the 

 antherozoids withdraw and soon perish. It is not yet certain whether 

 one or more of the antherozoids really penetrates into the substance of 

 the oosphere during the revolutions. As soon as it comes to rest the 

 oosphere takes on a cell-wall of cellulose and becomes an oospore, which 

 after an interval of rest begins to divide so as to form eventually a new 

 frond. 



DiCTYOTE^. — Although no members of this order are known on oiip 

 coast north of Xorth Carolina, the order cannot pass unnoticed in the 

 present article, because it forms a connecting link between the Fucaeac 

 and Phccosporew on one hand and the Floridecc on the other. The 

 species are olive-brown and form expanded membranous fronds. Three 

 kinds of reproductive organs are known, antheridia, spores, and tetra- 

 spores. All are formed by outgrowths from the superficial cells. The 

 tetraspores are formed, as the name implies, in fours in a mother cell, from 

 which they escape and then readily germinate. The spores are borne 

 singly in a mother cell. The antheridia are composed of a numbcF of 

 oblong cells, which become divided by numerous longitudinal and trans- 

 verse divisions into small cells, each of which contains an antherozoid. 

 The Uiciyotacecc resemble the Floridcw in having tetraspores and 

 spores which germinate without first passing through a zoosporic con- 

 dition. The action of the antherozoids is at present unknown, and the 

 spores of this order cannot be the product of a fertilization such as we 

 find in the Floridccv. 



Floeide^e. — This order is the same as the Rhodospermecc of Harvey's 

 Nereis. The species comi)osing it form a very natural group, and are, 

 ^'ith the exception of a few genera, entirely marine. Their color is al- 

 ways some shade of red or purple when they are growing in their nor- 



