128 THE OCEAN WORLD. 



Another species having a great resemblance to the Praya is 

 Galeolaria aurantiaca, or orange Galeolaria, which is represented 

 on the opposite plate (PLATE II.), borrowed from the fine 

 " Memoir of the Inferior Animals of the Mediterranean/' by Carl 

 Vogt. Here we find only two great floating bladders placed at each 

 extremity of a common stem, and serving the purpose of a locomo- 

 tive apparatus to the whole colony. This stem carries in like 

 manner polyps placed at regular intervals forming isolated groups, 

 provided each with its protecting bracts. But there is no special 

 swimming apparatus for each of these groups. Moreover, each 

 colony is either male or female. 



PHYSOPHORIDJE. 



These inhabitants of the deep are graceful in form, and are 

 distinguished by their delicate tissues and brilliant colours. Essentially 

 swimmers, supported by one or many vessels filled with air having 

 also, as in the previous Order, mostly true-swimming-bladders, more 

 or less numerous, and of variable form they float upon the waves, 

 remaining on the surface whatever may be the state of the sea. 

 They are natural skiffs, and almost incapable of immersion. The 

 Physophoridse form several families, the principal of which are the 

 Apokmiana (Fig. 43), the Stephanomina (PLATE III., p. 134), Physo- 

 phorince(F\g. 46), Physalmce (Fig. 49), and Velettince (Figs. 50, 51). 



The Apokmina contains but a single genus, Apokmia. The pretty 

 A. contorta of Milne-Edwards (Fig. 43), inhabits the Mediterranean, 

 and particularly the coast of Nice. This elegant species is often met 

 with in the Gulf of Villafranca, near Nice, and has been figured and 

 described by Milne-Edwards, Charles Vogt, and also by M. de Quatre- 

 fages, who asks the reader " to figure to himself an axis of flexible 

 crystals, sometimes more than a metre (forty inches) in length, all 

 round which are attached, by means of long peduncles or footstalks 

 equally transparent, some hundreds of bodies, sometimes elongated, 

 sometimes flat, and formed like the bud of a flower. If we add to 

 this garland of pearls of a vivid red colour an infinity of fine filaments, 

 varying in thickness, and giving life and motion to all these parts, we 

 have even now only a very slight and imperfect idea of this marvellous 

 organism." The swimming-bells in Apokmia contorta consist of a 

 mass having the form of an elongated egg cut in the middle. They 

 are arranged in a vertical series of twelves, and the axis which 

 supports them is terminated by the aerial vesicle or float. This 

 axis is always arranged in a spiral form, even in its greatest expansion, 



