Davenport. — Urnatella gracilis. 



PLATE V. 



ABBREVIATIONS. 



An. Anal aspect. Or. Oral aspect. 



etc. Scar of fallen bud. or. Mouth. 



cl. sec. Secreting cell. /'</• Stalk. 



di. ba. Basal disk. - rt. Rectum. 



ec'drm. Ectoderm. sto. Stolon. 



mu. Muscle fibre. vt. Yolk spherules. 



Fig. 30. Distal end of a richly branching stock of Urnatella, seen from the riglit 



side. X 56. 

 Figs. 31-45. Views of Urnatella as solid object (exc. Fig. 33). All X 18^. 

 " 31, 32. " Youngest stage " of Urnatella stock. Cf. Plate II. Fig. 15. 

 Fig. 33. View of somewhat older stage, as transparent object. Disk adhering to 



stolon. 

 Figs. 34, 35. Young stalks with median buds. 



Fig. 36. Entire stock of Urnatella, — three stalks arising from one basal disk. 

 " Median buds " arising. 

 " 37. Stalk with two lateral buds and one median. 



" 38. Stalk with profuse lateral budding on the median buds. Anal view, 

 branches displaced to the right and left. From segment c' two lateral 

 buds and one median have arisen ; from c, two lateral buds, one of 

 which has given rise to two individuals, the other to only one. 

 " 39 Stalk with branches, — oral view. Remnant of a median branch on seg- 

 ment F. From c' two lateral (?) buds; from K a stolon with two 

 individuals, and from L two stolons, the left with two individuals, 

 the right with one. 

 Figs. 40,41. Branching stocks with median and lateral buds. 

 Fig. 42. T^-pical lateral buds, each with two individuals. A median bud on next 



younger segment. 

 Figs. 43, 44. Right and left views of the same stock. The number of individuals 



is indicated in the diagram accompanying the figures (Fig. 44"). 

 Fig. 45. Left view of part of stock. Two stolons and one median branch from seg- 

 ment B (Fig. 45°). 

 " 46. Optical section of " youngest stage " of Urnatella stock. Stolon with two 



individuals arising therefrom. X 120. 

 " 47. View of cuticula and ectoderm at end of a stolon in a stock of the 

 "youngest stage," showing scar of former attachment to parent 

 stock. X 405. 

 " 48. Optical section of the basal plate of a stock showing three individuals 



arising from it, and its division into three segments. X 52. 

 " 49. Three individuals arising from an older basal plate. X 52. 



