EXPLANATION OF PLATE IL 



Fig. 



I, 2. CODOSIGA ALLIOIDES, S. K., vol. i. p. 337. — I, Umbellate adult colony-stock, or 

 zoodendrium, bearing numerous terminal clusters of associated collared 

 zooids, X 650 ; 2, a single zooid or animalcule with its body spherically, and 

 collar conically contracted, x 800. 



3. MONOSIGA GRACILIS, S. K., vol. i. p. 331, X I200. 



4-6. MoNOSiGA GLOBULOSA, S. K., vol. i. p. 332. — 4, Adult zooid, X 1500; 5, free- 

 swimming monadiform germ ; 6, subsequent attached condition of free- 

 swimming germ, the characteristic collar and pedicle being as yet 

 undeveloped. 



7-9. MoNOSlGA BREVIPES, S. K., vol. i. p. 332. — Exhibiting diverse protean contours, 

 X 1200. 



ID, II. CODOSIGA GROSSULARIA, S. K., vol. 1. p. 338. — lo. Normal adult colony-stock, 

 X 1000; II, smaller colony of three zooids only, having their collars coni- 

 cally contracted, and protruding numerous lateral, digitiform, pseudopodic 

 processes. 



12, 13. AsTROSlGA DISJUNCTA, From, sp., vol. i. p. 341. — 12, Free-floating colony as im- 

 perfectly delineated by De Fromentel, the lateral margins of the collars and 

 bases of the enclosed flagella only being represented, X 600 ; 13, the same 

 colony further enlarged, the details missing in the preceding figure being 

 added by the author. 



14. CODOSIGA PYRIFORMIS, S. K., vol. 1. p. 339, X I200. 



15-19. CODOSIGA FURCATA, S. K., vol. i. p. 339. — 15, Colony of two zooids as observed 

 by the author, x 1200; 16-19, imperfectly observed colony-stocks of various 

 dimensions, as figured by Stein in the year 1854 (' Die Infusionsthiere,' Taf. iii. 

 figs. 42 and 43), as probable young conditions of Epistylis digitalis or 

 Zoothamnitivi parasita, x 450. 



20-21. CODOSIGA Steinii, S. K., vol. i. p. 340, figured by Stein (' Wiegmann's Archiv,' 

 1849), as probable young conditions of Epistylis {Opercularia) nutans, 

 X 300. 



22-29. CODOSIGA (Epistylis) botrytis, Ehr. sp. {C. pulcherrifna,]3.s.-C\\i.),vo\.i. 

 p. 334. — 22, Colony-stock with pendulous zooids diagrammatically outlined, 

 X 1000 ; 23, smaller colony with three erect zooids ; 24, single zooid dividing 

 by longitudinal fission, the process having already extended through the body 

 and the proximal region of the contracted collar ; 25, two zooids assuming an 

 amoeboid condition, their collars and flagella being entirely retracted and 

 digitiform pseudopodia protruded from all parts of their periphery ; 26, a 

 single zooid emitting similar but more slender pseudopodic processes, the collar 

 and flagellum remaining extended, x 2000 ; 27, sporocyst with contained 

 spores derived from the encystment and segmentation of a single zooid ; 28, 

 earhest illustration of the species in which the existence of the characteristic 

 membranous collars is clearly indicated, as given by Frescnius in the 

 year 1858 ; 29, associated colony-stocks crowded upon a confervoid filament, 

 X 120. 



30. Desmarella moniliformis, S. K., vol.i. p. 341. —A free-floating colony-stock 

 of eight laterally united zooids, x 1200. 



31,32. MONOSIGA ANGUSTATA, S. K., vol. i. p. 330.— 31, Normal adult zooid, x 2500; 



32, immature or larval condition with the collar as yet undeveloped. 

 33-35. MONOSIGA OVATA, S. K., vol. i. p. 332. — 33 and 34, Typical zooids, x 1200; 35, 



zooid abnormally prolonged preparatory to dividing by transverse fission. 



