142 ANTHOZOA ASTEROIDA. 



According to Lamarck, this axis, under all its modifications, 

 is inorganic, containing neither vessels nor any portion of the 

 body of the polypes, but formed of matter excreted by them, 

 and afterwards thickened, solidified and depurated by affi- 

 nity.* Although this is rather, on Lamarck's part, the de- 

 duction of theory than of observation, yet the opinion is in the 

 main correct, and in correspondency with what had been long 

 previously maintained by Ellis. In the spicula of Alcyonidse 

 certainly we can find no traces of organism, and they lie seem- 

 ingly unconnected with the adjacent parts. The axis of Pen- 

 natula is a solid bone formed of laminse laid over each other, 

 softer and cartilaginous at each extremity where it seems to 

 be organically connected with the soft surrounding flesh : it is 

 evidently secreted, and deposited successively in layers, from 

 the inner surface of a thin pellucid membrane which Bohadsch 

 has described as investing it in the manner of a periosteum,f 

 and probably is endowed with that low degree of vitality 

 which preserves the horns, hairs and feathers of the higher 

 animals in that elastic and fresh condition which they have 

 only when in connection with living parts. The horny axis of 

 Gorgonia, notwithstanding some observations of Ellis which 

 apparently tend to a different conclusion,^ not more distinctly 

 organized, and is doubtless formed in the same manner as the 

 axis of Pennatula, for it is also of a lamellated structure, and, 

 according to Lamouroux, is invested with a similar perios- 



* Anim. s. Vert. ii. p. 78-80, 294, and 311. Mr. Couch is of a contrary opinion. 

 See his Corn. Faun. iii. p. 49. 



+ " Totum os membrana tenuis, lutescens, pellucida cingit, atque in utroque extremo 

 in ligamentum contorquetur, quod ex una parte in apice trunci pinnati, ex altera vero 

 in apice tmnci nudi inseritur." De Anim. Mar. p. 104. See also Corall. p. 214, 

 218, 224. 



f " Proceeding thus far, I was led on to observe what kind of communication there 

 was between the suckers (or polypes) and the bone of the animal. For this end I 

 examined several specimens, both dry, as well as those that were preserved in spirits, 

 with good magnifying glasses, and could distinctly trace an infinite number of minute 

 winding canals, that lead from the suckers through the flesh into those parallel longi- 

 tudinal tubes, which closely surround the bone or solid part on all sides. Perhaps 

 these may not improperly be called the periosteum ; for all along that side of those 

 tubes by which they adhere to the bony part, I could discover the pores very plainly 

 from whence the juices flow, that supply it with proper materials to answer this great 

 end." Soland. Zooph. 69. See also Couch's Corn. Faun. iii. p. 46-7. 



