EXPLANATION OF PLATE XIII. (continued). 

 Fig. 

 49-53. Ancyromonas sigmoides, S. K., vol. i. p. 247. — 49, Free-swimming animalcule, 

 X 1500; 50, animalcule fi.xed by distal termination of the single flagellum, 

 the dotted outline indicating the position alternately assumed by the body 

 with relation to the flagellum in the course of its rapid oscillations, x 2500 ; 

 51-53, showing the several progressive phases of oblique fission. 



54. Platytheca micropora, St., vol. i. p. 262. — Three lorica; w^ith their contained 

 animalcules attached to a joint of confer\-a ; at a two zooids, the result of 

 fission, occupy the same lorica, x 650 (Stein). 



55-64. OiKOMONAS MUTABILIS, S. K., vol. i. p. 250. — 55, A group of four monads 

 attached to vegetable fibre, showing at a and b normal sedentary forms, at c 

 an example ingesting food-matter at its lateral periphery, and at rf a young 

 and recently adherent example, not having yet developed a filiform pedicle, 

 X Scxj ; 56, an adult monad about to exchange its sedentary for a free- 

 swimming condition ; 57, the same monad detached and free-swimming, 

 still retaining an attenuation of its posterior and previously fixed extremity ; 

 58, typical free-swimming zooid ; 59 and 60, more aberrant forms ; 61, a 

 motile zooid dividing by longitudinal fission ; 62 and 63, spore-masses pro- 

 duced by segmentation of encysted animalcules ; 64, a young monad 

 developed from a spore. 



65-70. OiKOMONAS Steinii (S. K.), vol. i. p. 253.-65, A group of monads attached to 

 a spheroidal bacterial mass, x 650 ; 66, four monads similarly attached, 

 exhibiting a considerable irregularity of contour ; 67, a free-swimming 

 animalcule with branched posterior extremity ; 68, a free-swimming animal- 

 cule dividing by transverse fission ; 69 and 70, young free-swimming monads 

 (Stein). 



71. OiKOMONAS QUADRATA, S. K., vol. i. p. 254. — A group of five monads; at a 



and b, zooids ingesting food at opposite regions of the periphery, x Soo. 



72. OiKOMONAS OBLIQUA, S. K., vol. i. p. 252, filled with artificially administered 



carmine-particles, a portion of which it is discharging from its posterior 

 extremity, x 2500. 



73-77. OiKOMONAS ROSTRATA, S. K., vol. i. p. 253.-73, A group of monads attached 

 to a vegetable-fibre, x 800 ; 74 and 75, two attached monads, the one with 

 and the other without a posteriorly developed pedicle, x 1000 ; 76, an 

 example with an abnormally long pedicle ; 77, a free-swimming monad with 

 pedicle retracted. 



78-So. OiKOMONAS TERMO, J.-Clark sp., vol. i. p. 25 1. — 78, A group attached to vegetable 

 fibre, showing at <z a zooid dividing by longitudinal fission, at b an example 

 ingesting food-matter, and at c a young, recently attached and almost stalkless 

 zooid, X 1000 ; 79, a free-swimming monad ; 80, a free-swimming zooid 

 dividing by fission. 



