9 



tlio antliopodicie would be very quickly killed when the 

 colony is taken from the sea. As it is, colonies of 

 Alcyonium will retain their vitality for two or three days 

 if packed in damp seaweed. 



The number of the polyps in each colony increases with 

 its age, young l)uds being- formed between the older 

 polyps all through the life of the colom'. Each of these 

 buds is formed from an outgrowth of one of the superficial 

 canals (which may be seen to ramify in the mesogloea 

 near the surface of colony — PL L, fig. 3) joining a 

 corresponding depression from the ectoderm at the surface. 

 The young polyps thus formed remain in communication 

 with the neighbouring older polyps by the canal through- 

 out life, but no new canalicular communications with 

 these older polyps are formed at a later period excepting 

 quite close to the surface. The connection, therefore, 

 between the poljps composing the colony is that repre- 

 sented in Plate 1. fig. 5. The cavities of the older polyps 

 are here seen to extend to the base of the piece that is 

 represented in section, the cavities of the younger polyps ' 

 are connected at their bases with them by short canals, 

 and these in their turn may be connected with the bases 

 of still younger polyps in a similar manner. 



The colonial mesogloea appears to be at first sight a 

 homogeneous substance, but an examination with a simple 

 magnifying lens shows that it bears, firstly, a number of 

 small white calcareous bodies called " the spicules," 

 secondly, the canals above-mentioned, and, thirdly, a 

 number of very fine branching lines which might be 

 mistaken for capillary tubes. 



(i.) The spicules are small bodies varying in size 

 according to their age, but when fully formed O'l-O'onmi. 

 in length. They are .composed of calcium carbonate with 

 a sparse organic matrix. They vary very considerably in 



