54 



which ova are observed to be developed, their surfaces are 

 covered with numerous minute vibratory cilia which are in 

 constant action; tliese. when the ovum is free, whirl it about 

 in a very rapid manner from one part of the tube to another, 

 and at length into the abdominal cavitv. Here it moves 

 about from part to part, sometimes to the orifice at the base 

 of the stomacb, which immediately contracts to prevent its 

 escape ; at others it wanders into the chambers formed by 

 the septa' and to the base of the tentacula, and then again 

 returns to the base of the stomach. At length it passes 

 through the orifice into the stomach, where it is considerably 

 retarded in its action by the contraction and pressure of the 

 jraslric surface. After passinti the stomach, it escapes by 

 the mouth into the surroundinp; water. When escaped it 

 appears as if re-invigorated, and moves about with an energy 

 and activity truly remarkable. From the globular form, 

 which they have when they escape, they change first to an 

 oval, but vary in different instances and at different times. 

 The changes are sometimes rapid, and appear almost volun- 

 tary ; sometimes they are oval, at others they have an hour 

 glass contraction, and occasionally have rounded heads with 

 a tail like prolongation, and thus they vary to an almost 

 unlimited extent. Having at length found a spot on which 

 they rest to become fixed, fibres pass out from the base 

 to serve as roots, and the other parts undergo a remarkable 

 alteration in colour and appearance, becoming more elon- 

 gated, opaque, and dull, and the flesh appearing on the 

 surface ; tlie horny axis in a very rudimentary state 

 appears before it has attained one line in height; such is the 

 mode observed in the Gorgonifc. The young of the Alcyo- 

 nium differs from Ihi?, by diffusing itself into a thin crust. 

 Thus tliese curious creatures, first moving about with activity 

 and tlie irregularity of almost voluntary motion, then be- 

 coming fixed, rooted, and branched, present an instance of 

 metamorphosis as remarkable as any fabled by the Roman 

 poet. \V"hen the ova first appear they are of a very light 

 colour, but soon acquire a deep orange tinge. Under the 

 microscope they appear opaque, but with a good light they 

 are found to have a transparent zone. Their production is 

 entirely independent of any active influence of the polype; 

 by means of the polype an abundant supply of renovated 

 water passes over the ova and so keeps them in a healthy 

 condition. Both in the Gorgonia and Alcyouium, the whole 

 process of reproduction is so similar, that it is difficult to 

 draw a distinction between them. The ovaria and oviducts, 

 described by Cavolini as being found in the Gorgonia, I have 

 never detected; and the ova instead of escaping at the base 

 of the tentacula, as mentioned by him, I have found to escape 



