58 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Suborder BOTRYDIEiE. 



Fronds minute green nuicellar, spherical or pyriforin, with a rlii- 

 zoidal i)rocess at the base. Globose bodies i3roduced in the cells, from 

 Tvhich, when discharged, there is formed a large number of zoospores, 

 with two cilia, which conjugate. 



A small suborder, of which the developmeut is known only in a single species, B. 

 (jranulatum, of which Rostafinski and Woronin have given a full account. Probably 

 the suborder may require to be united with the Siphonea% a group abundant in the 

 tropics, but not strictly found with us. 



CODIOLUM, A. Br. 



(Named from the resemblance to species of Codium, a genus of marine alga?.) 



Frond unicellular, at the base prolonged into a tapering, solid, hya- 

 line stalk, above clavate, containing an oval chloropyllaceous mass, 

 which ultimately is transformed into a large number of spores, devel- 

 opment of spores unknown. 



The xiresent genus was founded by A. Braun on a species found by him at Helgo- 

 land in 1852 and described and figured in his work on unicellular algte. A second species 

 (C. XordensMoldiamim) was described by Kjellman. 



The genus is placed by Braun and Kjellman near Characium,hnt until the develop- 

 ment of the spores has been made out the position of the genus must remain doubtful. 

 Braun compares the spores to those of Codium, but states that he had never seen cilia. 

 In American specimens we have never seen the spores escape from the mother cell and 

 swim about by means of cilia, but, on the other hand, the wall of the mother cell dis- 

 solves and the spores thus set free begin to grow at once. It often hapi^ens that the 

 spores begin to grow inside the mother cell. The spores are oval and have a thick 

 wall. Each spore either gives off a projection at one end, which grows into a long 

 stalk, or else the contents of the sj)ore become divided into a small number of cells by 

 means of cross-partitions at right angles to its longer axis, thus forming a short fila- 

 ment, each cell of which gives off a stalk as previously described. There results in 

 the last case a dense cluster of individuals, which adhere together by their bases. It 

 may be that what we have seen was only the hypnosporic condition of the plant, and 

 that Braun had examined a stage in which motile spores existed. Occasionally one 

 tinds two spore-bearing cells on a single stalk, one always being very much smaller 

 than the other. The second cell is lateral and may be nearly sessile on the stalk or 

 furnished with a short secondary stalk of its own. 



Our plant recalls the hypnosporic condition of Botrydhim (jranulatum, and in the 

 Algse Am. Bor. Exs. it was distributed under the name of B. (jretjarium. As the devel- 

 opment is so little known, we have now thought best to retain the name Codiolum, on 

 the supposition that our species is the same as that of Braun. The study of the de- 

 velo^iment is rendered difficult because the plant grows inextricably entangled with 

 other small algae. 



C. GREGARIUM, A. Br. (C. gregariiim, Braun, Alg. Unicell., Gen- 

 era nova et minus cognita,p. 20, PI. 1. — Botrydinm (jregarium^ Farlow, in 

 Alg. Am. Bor. Exs., :N'o. 99.) 



Cells densely aggregated, average length of cells, including stalk, 



