184 



1. Exuviaella lima, Ehr. ; Saville-Kent, Manual of Infusoria, 



1882, Vol. i. p. 4:62. Biitschli in Bronn's Klass, und Orel. d. 

 Thier-Reichs, Abt. ii. p. 1002, pi. 51, f. 2, a-b-c. 

 Rock-pools, Coogee Bay. 



2. Prorocentrurn micaud, Ehr. ; Kent, 1. c. Vol. i. p. 40 1, pi. 25, 



f. .37-39. Biitschli, 1. c. p. 1002, pi. 51, a-b. 



The typical form of this species was obtained from rock-pools 

 at Coogee Bay ; I also found what may be a variety in gatherings 

 from the tow-net. The body is elongate, narrowed towards each 

 end, and the spine is longer and liner ; the cuirass is distinctly 

 and coarsely cribate. 



.Surface, off" Green Point ; rock -pools, Coogee Bay. 



Order DINIFERA, B<-r<jh. 

 family Dixopiiyida. 



3. riudacroina nijia, Stein. ; Biitschli, I. c. p. 100!), pi. 55, f. 2. 

 Surface, off' Green Point, P. J. 



4. Dhwjdiijsis laiois, Bergli. Morp. Jahrbuch, Vol. vii. p. 224, 



pi. lo', f. 55. 

 Surface, off" Green Point, P. J. 



5. D. ]iomuncidus, Stein. ; Biitschli, i.e., pi. 55, f. 3, b. (Plate 



xxviii., figs. 9-16.) 

 A large series of specimens of this fine species in various stages 

 of development were obtained from the surface off Green Point. 

 The youngest specimens met with had the form of a round disc, 

 Avithout any trace of the transverse groove. During my 

 e.xamination of the material obtained by the tow-net, I saw 

 some hundreds of examples exhibiting almost every gradation 

 between tlie disc-like form and tliat of the adult. The various 

 changes during the development appear to be as follow : — The 

 round disc assumes an oblong shape, and the transverse groove 

 appears at the anterior end of the body, which is slightly 

 narrower than the posterior ; afterwai'ds the longitudinal furrow 

 is formed by the gradual extension of the membranous crests 

 downwards, from the margin of the transverse groove. The next 

 change is marked by the growth of the medium spine-like 

 prolongation of tlie body, and afterwards by the formation of a 

 similar, but nmch shorter, process at the base of the dorsal surface. 

 Although the above mentioned stages have not been followed out 

 in the life history of the individual, I am of the opinion that the 

 presence of a large series of intermediate forms — gradually passing 

 from the discoidal stage up to what I consider to be the adult — 

 in one gatlun-ing, render it higldy probable that they are simply 

 the various stages in the development of one and the .same species. 

 The cell contents are green, and the cuirass is ornamented by the 

 same cribriform markings in all the different forms. Several 

 specimens were seen in process of division, the line of cleavage 



