26 Edmund B. Wilson 



The state of our knowledge is too imperfcct to admit of this Sug- 

 gestion being fully carried out at present, but I submit that the evidenee 

 is quite sufficient to warrant farther examination of the comparisou. 



Naples, Sept. 14, 1883. 



Explanation of the Figures. 



Ali of the figures, except the diagrams Nos. 14, 1.5 and 16, are drawn with the 

 camera lucida. To avoid needless repetition, the general figures 5, 10 and 13 have 

 each been construeted from two or three sections, and the histological detail in 

 these figures is necessarily somewhat diagrammatic, although conveying a faithful 

 picture of the points which are important for my purpose. The lettering, which is 

 uniform throughout, is as follows. 



a. a. Openings of the finer canal-system into the main longitudinal canals. 



e Brauches of the canal-system. 



ex. Calyx-teeth of the bud. 



d.f. Dorsal or ectodermic mesenterial filamenfs. 



d.s. Dorsal septa. 



d.w. Dorsal wall of stomodaeum. 



ec. Ectoderm. 



e.f. Entodermic mesenterial fiiaments. 



en. Entoderm. 



m Mouth. 



mes. mesoderra. 



11 Fine branches of the canal-system. 



oe Oesophagus. 



ov Ova. 



s Septa. 



sii. Spicules. 



V Vacuoles in the entodermic fiiaments coutaiuing foreign bodies. 



V. s. Ventral septa. 



Piate 1. 



Fig. 1. Young polyp of Clavulaiia ochracea , 14 days old, before the appearance 

 of the stolon. Drawn from a preserved specimen. The dorsal fiiaments, 

 d.f., are less thau half as long as the others. The line from e.f. extends 

 to the dorso-lateral entodermic filament. X 65. 



Fig. 2. A longitudinal dorso-ventral section through the same individuai, pass- 

 ing through the whole length of the dorsal filament, d.f., and showing 

 the connection ofone of the ventral fiiaments, e/., with the Oesophagus. 

 X 130. 



Fig. 3. View from the dorsal or inner side of a young bud oi Alcyonvtm inilma- 

 tum and a portion of the canal-system with which it is connected. The 

 rudimentary dorsal fiiaments are shown at d.f. ■ vl.f. are the ventro- 

 lateral, dl.f. the dorso-lateral, and v.f. the ventral fiiaments. The 

 ventral and ventro-lateral fiiaments of one side have fused together. 

 X 80. 



