Genera Salpingceca and Polyoeca. 189 



My drawings and preparations show that, in colony forma- 

 tion and in the shape of lorica, the specimens seen by me 

 differ considerably from those shown in the figures of S. Kent. 

 I am reluctant to establish a new species name in this little- 

 known group, but unfortunately S. Kent's specific name of 

 dichotoma would be a positive misnomer for this form. It 

 will be seen (PI. VI. fig. 2) that from one basal individual as 

 many as five daughter individuals may arise. The form of 

 the lorica is very different from that shown in Kent's figures, 

 the base tapering down very gradually; also the body nearly 

 fills the lorica, whereas Kent shows the body as being about 

 one-half the width of the lorica. The stalk of Polyoeca 

 dichotoma is shown as branching by Kent. I believe that 

 this was an error of interpretation. Certainly I have never 

 found a stalk branching in my species, although, without 

 careful observation, the crossing of two stalks (PI. VI. fig. 2) 

 might easily be mistaken for such. Under these circum- 

 stances I am compelled to distinguish this species from that 

 of Kent, and, from the bushy form of full-grown colonies, the 

 name Polyozca dumosa would appear to be suitable. 



The form is very small, the lorica being 10' 5 fi in length 

 and 4*5 /uu in breadth, while the cell itself is only 6 /x long and 

 4 fju broad. The flagellum is at least twice as long as the 

 cell-body and is generally in movement along its whole 

 length. The collar is usually very well expanded (PI. VII. 

 figs. 3 & 4). It is worthy of note that in most of the 

 marine forms seen by me the collar was expanded into the 

 cup-shaped form which Kent always depicts. This is not the 

 case with freshwater forms, or rarely so, the collar being in 

 them more cylindrical in shape. France^ being more familiar 

 with freshwater forms, was led by this fact to remark that 

 " nur in ganz vereinzelten Fallen ist das Collare tatsachlich 

 glockenformig," but, in the majority of cases, Kent's figures 

 are probably correct in this respect, as he worked a great 

 deal with marine Choanoflagellata. 



The nucleus, not shown in most of Kent's figures of 

 P. dichotoma, is seen in preparations stained with carmalum 

 or treated with iodine solution (PI. VII. figs. 5 & 6). Although 

 very obscure, it can be seen near the base of the flagellum. 

 Like most of the nuclei in Choanoflagellata, it consists of a 

 round evenly staining body, with a central deeply staining 

 karyosome. I have not seen a blepharoplast clearly. 



The main interest of this form lies in its faculty for colony 

 formation. Division occurs as described above for Salpin- 

 gceca, the two resulting cells lying somewhat obliquely in the 

 cell (text-fig. 3). The difference between Salpingceca and 



