Propagation among the Lower Animals. 155 



III. Aplidmm verrucosnm, the Warty Sea-fig. — Early in Oc- 

 tober, the oyster-dredgers of Newhaven, some of whom have 

 been in my employment nearly twenty years, brought a quan- 

 tity of marine products to me, which had beencollected to the 

 south or south-east of Inchkeith, in the Frith of Forth. Among 

 these was a gelatinous looking, but solid, compact substance, 

 which, being suspended by silk threads in a large glass jar of 

 sea-water, proved of olive-green colour and approached the form 

 of an irregular parallelopiped above three inches long, and 

 equalling perhaps three cubical inches of solid contents. The 

 whole was covered with very low prominences almost even with 

 the surface. 



In a short time the prominences developed as a profusion of 

 short projecting cylindrical orifices, each fashioned as a lip with 

 a smooth, even edge, wherein were attracted by a powerful 

 current and absorbed the neighbouring buoyant particles. After 

 the lapse of several hours the bottom of the jar was covered by 

 a quantity of dark ovoidal pellets, discharged from all points of 

 the common mass, now clearly discovered to be a vast aggre- 

 gate of animals thus in activity, each not exceeding a line and a 

 half in diameter, united and incorporated together. 



The numerous currents of buoyant particles and their ab- 

 sorption, the multitude of creatures in action, their sudden 

 crouching down and rising again to resume it, is a spectacle in- 

 teresting to the naturalist. It seemed to me, as with the 

 amphitrite, an animal apparently much higher in the scale, that 

 they were roused by the presence of muddy matter; and that 

 they would clear the water of it. 



The approaching maturity of numerous internal corpuscules 

 converted the olive-green of the subject to a brownish colour ; 

 and as they became more vivid the skin seemed to become daily 

 thinner. 



At length a number of spinulae, narrowly resembling those 

 of the preceding paragraph, appeared in the vessel. There 

 could be no doubt of their origin. But they vanished speedily, 

 though diffusing specks remained as before. 



Having altered the position of the specimen and introduced 

 smaller vessels below, so as to receive whatever it might produce. 



