EXPLANATION OF PLATE XXL {contmiie({). 

 Fig. 

 30-32. COLACIUM CALVUM, St., vol. i. p. 395 (Stein). — 30, Social colony-stock, x 400 ; 

 31 and 32, detached, free-swimming animalcules in extended and contracted 

 states. 



33. COLACIUM ARBUSCULA, St., vol. i. p. 394. — Tree-like colony-stock, x 500 (Stein). 



34-38. COLACIUM VESICULOSUM, Ehr.. vol. i. p. 395 (Stein). — 34, Sedentary colony-stock, 

 X 600 ; 35, detached, free-swimming animalcule ; 36-38, successive de- 

 velopmental phases following on the attachment of a motile zooid, and 

 resulting, through further subdivision, in the building up of a more or less 

 extensive sedentary stock. 



39-41. COLACIUM Steinii, S. K., vol. i. p. 395. — 39, Erect colony-stock, x 350; 

 40, arborescent stock, x 700, showing variety of contracted or contorted 

 forms assumed at will by the component animalcules ; 41, animalcule in an 

 encysted state, with the body-contents divided into sporular elements. 



42. Cryptoglena conica, Ehr., vol. i. p. 419, X 500 (Ehrenberg). 



43-45. Cryptoglena angulosa, Carter, vol. i. p. 420 (Carter).— 43, Normal aspect ; 



44, example enclosing four endogenously developed germinal bodies ; 



45, lateral aspect, x 500. 



46-51. Distigma PROTEUS, Ehr., vol. i. p. 418 (Stein). — 46, Normal biflagellate ani- 

 malcule, X 500 ; 47 and 48, old, non-flagellate, and repent zooids {Proteus 

 tenax-, O. F. Miiller ?) ; 49 and 50, young free-swimming animalcules ; 51, 

 still younger monoflageUate example {Monas pKitctiim, Ehr.). 



52, 53. Zygoselmis nebulosa, Duj., vol. i. p. 417 (Stein), x 1000.— 53, Example with 

 body distended by ingested diatoms. 



54-59. EUTREPTIA VIRIDIS, Pty., vol. i. p. 416. — 54 and 55, Normal free-swimming 

 animalcules, x 250 ; 56, repent example ; 57, sporocyst burst and liberating 

 green amcebiform germs, x 400 ; 58, amcebiform germs more highly mag- 

 nified ; 59, young monoflageUate zooids, x 250. 



