EXPLANATION OF PLATE II. 



FIG. 



i, 2. CODOSIGA ALLOIDES, S. K. 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., X I2OO. 



4-6. MONOSIGA GLOBULARIS, S. K. 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. MONOSIGA BREVIPES, S. K. Exhibiting diverse protean contours, x 1200. 



10, ii. CODOSIGA GROSSULARIA, S. K. 10, Normal adult colony-stock, x 1000 ; 

 1 1, smaller colony of three zooids only, having their collars conically con- 

 tracted, and protruding numerous lateral, digitiform, pseudopodic processes. 



12, 13. ASTROSIGA DISJUNCTA, From. sp. 12, Free-floating colony as imperfectly 

 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., x 1200. 



15-19. CODOSIGA FURCATA, S. K. 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 Zootham- 

 nium Jxzrasila, x 450. 



20, 21. CODOSIGA STEINII, S. K., figured by Stein (Wiegmann's 'Archives,' 1849), as 

 probable young conditions of Epistylis (Opercularicf) nutans, x 300. 



22-29. CODOSIGA (EPISTYLIS) BOTRYTIS, Ehr. sp. (C. pulcherrima, Jas.-Clk.). 



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, earliest illustration of the species in which the existence of the 

 characteristic membranous collars is clearly indicated, as given by Fresenius 

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

 filament, x 120. 



30. DESMARELLA MONILIFORMIS, S. K. A free-floating colony-stock of eight 



laterally united zooids, x 1 200. 

 31, 32! MONOSIGA ANGUSTATA, S. K. 31, Normal adult zooid, x 2500; 32, immature 



or larval condition with the collar as yet undeveloped. 

 33-35. MONOSIGA OVATA, S. K. 33 and 34, Typical zooids, x 1200; 3$ zooid 



abnormally prolonged preparatory to dividing by transverse fission. 



