which, like the group Pennatuh'dfB, have a stout axis, with branches either 

 side, arranged regularly in plume-like style, or a " very slender stem and very 

 short lateral .polyp-bearing pinnules or processes along it (the Yirgularidae) ; 



* * * and some of these have a slender stem, and the polyps arranged 

 along one side of it (the Pavonariadas) ; and still others a terminal cluster of 

 polyps (the Umbellularida"). 



The most of these species secrete a slender horny axis, and have slender cal- 

 careous spicules among the tissues, somewhat like those of Gorgonida;."* 



This internal horny axis is also described as " bony"f by other writers ; it is 

 covered with a fleshy substance, of a consistence like that of the Actinia, which, 

 being largely composed of water, leaves but little solid matter when dried, 

 which is brushed off or crumbles away with very little handling. 



In the Pennatute, or Sea-pens, the central stalk or axis is of moderate length 

 and the pinnce rather long, presenting the appearance of a feather ; or as La- 

 marck said, "it seems, in fact, as if nature, in forming this compound animal, 

 had endeavored to copy the external form of a bird's feather." 



" In some genera, Virgularia and Pavonaria, to which the name of " sea- 

 rushes" has been given, the central stem is very much prolonged, some of them 

 measuring between three and four feet in length. The polypiferous lobes are 

 comparatively short." ^ 



To either the sea-pens (Pennatulids), or the Umbellate corals (Umbellulari- 

 dffi), I believe these specimens belong; and of the two groups indicated, J am 

 inclined to place them in the latter ; said group is characterized by a " Polyp- 

 ary free, simple elongated, with the polyps at the summit ; axis stony, inarticu- 

 late, covered with a fleshy cortex ; polyps large, terminal, arranged in an um- 

 bellate manner at the end of the polypary."J 



Figuier remarks that " Les Ombellulaires ont une tres-longue tige, soutenue 

 par un os de meme longueur et terminee au sommet seulement par un bouquet 

 de polypes."|| 



" The physiological phenomena which the Pennatula present is extremely in- 

 teresting, since it exhibits the example of a truly composite animal, that is, one 

 in which animals, more or less in number, really perfect so far as comports with 

 the grade of organization to which they belong, form part of a common living 



* * * body, serving as an intermedium for nutrition to all the individuals, 

 so that they are all nourished together in a mediate manner by means of this 

 common portion of which they form a part. 



The nutriment which favorable circumstances have placed within the reach 

 of one individual, nourishes that individual first, and then, by extension, nour- 

 ishes the common stem ; and thus the other polypi, which constitute organic 

 portions of it, receive their share."l| 



* Ibid, page 91. 



t Dallas, in " Orr's Circle of the Sciences." 



§ Dallas, Ibid. 



{Manual Nat. Hist. Travellers, page 357. 



II La Vie et les Moeurs des Animanx, Paris, 1866. 



f Cuvier ; Mollusca and Radiata, by Griffith and Pidgeon. London, 1834. 



