APPENDIX 283 



fragmentary state of our knowledge of Labyrinthula, to accept the conclu- 

 sion that the (inferred) fusion between the pseud opodia after encystment 

 represents this important event in its life-history. 



We are therefore inclined to regard Labyrinthula as a colonial 

 organism of which the units remain in connection by their pseudopodia. 

 As the result of drying they may pass into the encysted stage, in which 

 they are isolated from their fellows by the cyst-walls. It appears prob- 

 able, from Zopfs observation, that, on resuming activity, they may 

 again unite with their fellows to form a colony. Other stages of the 

 life-history are at present unknown to us. 



With Labyrinthula Zopf associates the genus Diplophrys (Archer), 

 Cienk. The species named Diplophrys stercorea by Cienkowski (2) is a 

 colonial organism, with simple thread-like pseudopodia, living on horse- 

 dung. It can hardly belong to the same genus as Diplophrys Archeri 

 (Barker), with ramifying pseudopodia and a distinct though membranous 



FIG. 3. 



2. CMamydomyxa Ifihyrinthuloldes, Archer. The animal in the free state partially emerged 

 frcnn the many-layercil cyst. A small encysted mass is seen at c between the envelopes of the 

 latter. At o and elsewhere in the main body of the protoplasm, as well as in outlying portions, 

 invested food particles are shown. The oat-shaped corpuscles are seen on the stiff extended 

 filaments, x about 150. (From Lankester, after Archer.) 1 and 3, I.abi/rinthulrt riteltiiw, 

 C'ienk. 1, a colony crawling upon an alga. The units are partly aggregated, partly extended 

 on the network of stiff extended pseudopodia. x about 120. 3, part of the network, x about 

 250. At p and p 1 several units have fused into a common mass ; , s, units which have assumed 

 the spherical shape and are stationary. 4-7, Labyrinthula macrocystis, Cienk. 4, a single unit 

 giving out three pseudopodia ; n, its nucleus ; x 320. 5, a group of encysted units invested in 

 a tough secretion, x about 250 ; f> and 7, encysted units the contents of which have divided 

 into I'our, x about 320. (From Lankester, after Cienkowski.) 



test. Both forms, together with Labyrinthula and Chlamydomyxa, may 

 provisionally be regarded as related in one direction to outlying members 

 of the Gromiidea, here included in the Foraminifera, and in others to the 

 Heliozoa and the Proteomyxa. The grounds for regarding the two latter 

 genera as especially related have vanished in the light of fuller knowledge. 



LITERATURE. 



1. Cienkowski. Ueber den Ban u. Entwickelung der Labyrinthnleen. Arch. 



f. inikr. Anat. Bd. iii. (1867), p. 274. 



2. Ueber einige Rhizopoden und vevwandten Organismen. Ibid. Bd. 



xii. (1876), p. 44. 



3. Lankester, E. II. Article "Protozoa" (Class Labyrinthulidae). Encyclo- 



paedia Britannica, 1891. 



4. Zopf, jr. Zur Kenntniss d. Labyrintlmleen, eine Fain. d. Mycetozoen. 



Beitr. zur Phys. u. Morphologic niederer Organismen, Heft 2 (1892), 

 p. 36, and Heft 4 (1894), p. 60. Leipzig. 



