58 



HARDWICKE'S SCIENCE-GOSSIP. 



the pulp, incessantly increased by new supplies of 

 nutriment from the polype, is constrained and forced 

 into its original direction, so that the extremities of 

 the tube, which have remained soft and pliant, are 

 pushed onwards, the downward shoot becoming a 

 root-like fibre, and the upper continuing the poly- 

 pidom, and swelling out as before at stated in- 

 tervals, into cells for the development of other 

 polypes." 



The materia] of the polypidom, or hard sheath 

 protecting the soft pulpy cceuosarc, appears to be 

 analogous to horn or condensed albumen. There has 

 been much disputing about the relations subsisting 

 between the sheath, the ccenosarc, and the polypes, 

 as to which produces the other, and whether the 

 three are more or less independent of each other. 

 The following summary is given : " The growth of 

 the two parts (pulp and polypidom) is coetaneous, 

 for although the expansion of the membrane appa- 

 rently precedes that of the pulp, it is nevertheless 

 dependent on the growth of the latter for its ex- 

 pansion, and regulated by it : there is but one life 

 and one plan of development in the whole mass, and 

 this depends, not on the polypi, which are but secon- 

 dary and often deciduous parts, but on the general 

 fleshy substance of the body." 



In the Gorgoniadce, instead of a branching ccenos- 

 arc (m, fig. 28), and individual polypes connected 

 therewith by pedicels, the whole being encased in a 

 horny sheath, we find on the outside a semi-carti- 

 laginous vitalized mass, the coenosarc {a, fig. 29) 

 investing a central axis, the sclerobasis, of a horny 

 material (b, fig. 29), which gives stiffness and sup- 

 port to the whole structure. The eight-armed 

 polypes (<;) are neither lodged in nor attached to 

 this internal polypidom, but occupy cavities in the 

 external ccenosarc, communicating with the latter 

 and with each other only by means of the canals 

 which run through the whole mass for the purposes 

 of the general nutrition. These canals appear like 

 dots (d, fig. 29). 



Fig. 29. Transverse section of Gorguniu verrucosa, x 5. 



We have seen how the reproduction of the species 

 is accomplished in the Hydra and in the compound 

 Hydrozoa; but in these Corallaria we have no mul- 

 tiplication by fission, by deciduous buds, or by me- 

 dusiform.larvae escaping from external vase-shaped 

 " ovi-capsules " like seed-pods. The depths of ocean 



have hidden from our inquiring eyes the secrets of 

 the babyhood of the young Gorgonia. We believe 

 that he originates from an egg formed somewhere 

 on the inner surface of the lining of the canal under- 

 neath the abdominal cavity of the polype, somewhat 

 after the ovarian plan of the Sea-anemone, the Gor- 

 gonia-polypes being, in a general sense, actiniform 

 — the Zoanthus, with its creeping, root-like processes, 

 reminding us of the mycelium of the fungi, being 

 apparently the connecting link between the solitary 

 Actinia and these compound forms. But the 

 transformation of this egg into the sprouting 

 zoophyte has not been observed in the same 

 satisfactory and conclusive manner as the birth 

 and growth of the Hydrozoon, the story of which 

 (borrowed from Johnston) we have just related; 

 but there seems to be every reason to believe that 

 a very close resemblance exists between the first 

 stages of the nascent Hydrozoon and of the 

 Gorgonia. 



Some of the Gorgonice throw out branches, which 

 remain separate— 67. pinnata (fig. 24), for example. 

 In others, such as G.flabellum, the twigs inosculate 

 or anastomose, forming a network reminding us of 

 a skeleton leaf. In fig. 30 we show a portion of 

 the typical Sea-fan, magnified sufficiently to exhibit 

 the circular pits in the ccenosarc occupied by the 

 polypes. 



Fig. 30. Small portion of Gorgonia flabellum, x 5. 



We also give a figure (31) of Ms hippuris, in 

 which (a) shows a portion of a branch covered with 

 the ccenosarc and studded with polypes. Below 

 this portion, the investments have been removed, 

 to display the axis, composed of alternate joints 

 of (b) horny, and (c) calcareous matter. The main 



