Phytozoa.] 



MUSEUM OF ANIMATED NATURE. 



415 



large cross of wood with a heavy weight in the cen- 

 tre, and nets properly secured to each Hmb ; this is 

 let down from a boat by means of a rope duly 

 secured ; the boat is then rowed over the coral beds, 

 and the stems and branches are broken off by the 

 machine nnd entangled in the nets. It is thus that 

 the coral fishery off Trepani in Sicily is carried on, 

 and also on the Barbary coast, where, however, they 

 do not drag for it beyond three or four leagues from 

 sliore, and in water not deeper than fifteen or twenty 

 fathoms. Tliis method of collecting it is very rude, 

 anl no doubt much is lost. 



"in ail ages and countries," says Lamouroux, 

 "men have acknowledged the beauty of coral. War- 

 riors have employed it in the decoration of their 

 arms, and women in that of their dress. The phy- 

 sicians of the middle ages looked upon it as a uni- 

 versal remedy; and the priests of ancient religions 

 as an object acceptable to the gods." In the pre- 

 sent day the value of coral is very ftir less than what 

 it was formerly. 



To the present group Corticifera, familly Corallidae, 

 belongs the genus Jsis. In this genus the axis is 

 arborescent, and composed of alternate joints of 

 wliite calcareous and dark horny matter, or rather 

 of a calcareous stem and branches, separated into 

 articulations by horny intervals of greater or less 

 extent. The calcareous joints are longitudinally 

 .striated. The whole is covered with a tiiick fleshy 

 integument in which the polype -cells are abundantly 

 scattered. The polypes are minute. Fixed to the 

 rock, these jointed corals yield to the rolling waves 

 or currents of the water. Fig. 3837 represents the 

 Isis hippuris, or Horsetail coral : a portion is denuded 

 to show the joints, and one branch is covered with 

 its living investment studded with polype-cells; the 

 right-hand figure is the section of a portion showing 

 the axis, and the thick fleshy rind, with its polype- 

 cells displayed, and polypes contracted within ; a 

 single polype is also figured; and a transverse sec- 

 tion of the stem. 



Among those genera in which the axis is entirely 

 hornlike and elastic, we may notice Gorgonia, of 

 which some species resemble bending osiei-s, and 

 others present the form of reticulated lans ; Antipa- 

 thes, with branching stems, reticulated expansions, 

 or feather like ramifications; Plexaura; and Prim- 

 iioa. With respect to the latter, it is characterised 

 by Lamouroux as tree-formed and dichotoraous; the 

 poljpes covering the axis, which is hard and horny, 

 in the form of long pyriform bodies with imbricated 

 scales, serving as pulype-cells. The tentacles of 

 the prominent polypes are conical, and in repose 

 fold over the mouth. One species only is known, 

 Piimnoa lepadifera, from the Norway coast. A 

 branch of this coral is represented at Fig. SS.'JS, with 

 the polype distinct in two views. The entire zoo- 

 phyte is Irom six to ten or twelve inches in height. 



Another family of the Corticifera is termed Pen- 

 natulidi£. 



The Pennatulidae, as characterised by M. de 

 Blamvillc, are polypiform, provided with eight pin- 

 nated tentacles, and regularly scattered on one 

 part of the surface of the general sul)stance. The 

 form of the whole is delerminate. The mass is com- 

 posed of a central and solid axis, surrounded by a 

 fleshy cortical substance, olten very thick, and sup- 

 ported by calcareous minute needles more or less 

 numerous. 



All or nearly all are unattached, and float in the 

 waters of the sea. Many are phosphorescent. 



Whatever may be the general form of the Penna- 

 tulidie, one of the extremities is always devoid of 



Eolypes, and this part, more or less elongated, has 

 een compared to the quill of a feather, while the 

 polypilerous portion resenibie* expanded barbs. 

 These zoophytes have in fact a bilateral symmetry 

 of which other groups show us no similar examples. 

 In the genus Umbellularia the polypes, which are 

 elongated, with eight strongly pinnated tentacles, 

 are arranged so as to form an umbel at the end of 

 a long tetragonal cortical mass, which contains a 

 tetragonal calcareous axis. Fig. 3839 represents 

 Umbellularia enciinus, from the Greenland Seas; a 

 portion of the stem is laid open to show the axis. 



In V'irgularia there is a long central stem, with 

 reiiular lateral fleshy branches, on which the polypes 

 with ciliated tentacles are arranged in rows. Fig. 

 38-iO represents the Virgularia mirabilis (Pennatula 

 miriibilis, Mii!!er). In Pennatula the general form 

 is that of an expanded feather. The polypes, which 

 are entirely retractile, and have eight ciliated ten- 

 tacles, are iiregulaily disposed on the retral edge 

 of lateral pinnules, or barbs, symmetrically placed 

 along each side of the central stem with a simple 

 calciireous axis ; and these pinnules are prolonged 

 into a bulbiforui expansion pierced by four terminal 

 openings. Fig. 3841 represents Pennatula grisea. 

 In the warmer parts of tlie ocean, numbers of Pen- 

 nati.lae, or Sea-pens, may be observed floating. Cu- 

 vier says that they can propel themselves by the 

 contraction and dilatation of the fleshy investment 

 of their simple calcareous axis, and the simuita-neous 



action of the tentacles of the polypes. This, how- 

 ever, has been denied by subsequent observers, who 

 assert that they are cimipletely passive, being merely 

 carried along like sea-weed by the current. 



Mr. Darwin observed at Bahia Blanca hundreds 

 of a species of Virgularia (V. Patachonica) project- 

 ing at low water from the muddy sand. When 

 touched or pulled, they draw themselves in suddenly 

 and with force, so as nearly or quite to disappear. 

 By this action, he observes, the highly elastic axis 

 must be bent at the lower extremity, where it is na- 

 turally slightly curved, and he considers that it is 

 by this elasticity that the zoophyte is enabled to rise 

 again through the mud. The stem varied in length 

 from eight inches to two feet, and had alternate 

 rows of polypes on each side. 



The reproduction c( the Corticiferous Polypiaria 

 is from germs which are developed on interna) con- 

 volute membranes, and which when mature escape 

 through the common oriiice of the polype, or in 

 some manner not clearly ascertained. 



Let us now pass on to the compound tubular Poly- 

 pifera, the " Polypes i\ Tuyaux" of Cuvier, in part 

 the Nudibranchiata of Dr. Farre, which in general 

 aspect agree with the Bryozoa already noticed, and 

 with which till recently they have been associated. 

 The polypes, however, are far less complex in struc- 

 ture, being simply hydriform ; yet it must be con- 

 fessed that further observations are necessary before 

 the strict boundary-line between the Bryozoa and 

 the simpler tubular polypes can be rigidly laid 

 down. Perhaps, indeed, in a popular work like the 

 present it would be allowable to throw them to- 

 gether ; yet in so doing we should not treat our sub- 

 ject with proper accuracy. This difficulty appears 

 to have been felt by Professor Jones, who, in his 

 valuable ' Outline of the Animal Kingdom," speak- 

 ing of the " Polypes it Tuyaux," says that the group 

 " would seem indeed to comprise animals distin- 

 guished from each other by so many important cir- 

 cumstances, and yet so intimately related by exter- 

 nal configuration, that it is difficult to separate them 

 or leave them in the same group." We have ven- 

 tured to separate them ; and that on the grounds of 

 organization. " In the uniciliated tubular polypes 

 the common body of the animal, instead of encrust- 

 ing a solid skeleton, is enclosed in a horny sheath, 

 which it traverses like the pith of a tree, following 

 all the ramifications of the branched stem of the 

 polypary : to the central part are attracted at inter- 

 vals cells opening externally, in which the polypes, 

 which provide nourishment for the whole, are 

 lodged." These characters attach to the Bryozoa ; 

 but their structure, as we have said, is far more com- 

 plex. 



Of graceful form, the uniciliated tubular polypes 

 cannot but attract observation ; they abound on 

 our own shores, and specimens may be procured with 

 little difficulty ; the very tide carries many to our 

 feet. These delicate arborescent zoophytes are for 

 the most part phosphorescent. Mr. A. H. Hassall 

 (' Ann. and Mag. of Nat. Ilist.,' June, 1841) states 

 that he has ascertained that all the more transparent 

 zoophytes possess highly luminous properties. This 

 fact he first discovered in a specimen of Laomedia 

 gelatinosa, one of the Tubulariae, and subsequently 

 in a great variety of other species. 



" Imagination," he adds, " can scarcely conceive 

 a more beautiful spectacle than would be furnished 

 by the shining of countless myriads of these tiny 

 lamps lighting up the dark recesses and caves of the 

 ocean." " I had lately (he co'itinues) an opportu- 

 nity of beholding this novel and interesting sight of 

 the phosphorescence of zoophytes to great advantage, 

 when in one of the Devonshire trawling boats which 

 frequent this coast (Ireland). The trawl was raised 

 at midnight, and great quantities of corallines were 

 entangled in the meshes of the network, all shining 

 like myriads of the brightest diamonds." 



The numerous genera into which these elegant 

 zoophytes with flexible stems and branches enclos- 

 ing a living thread are divided, range themselves 

 under two families — Tubulariae and SertulariiE. 

 In the former we are presented with simple or 

 branched horny tubes, from the open extremities or 

 branches of which the polypes emerge and expand 

 their tentacles. One species, the Tubulaiia indivisa, 

 found on our shores, resembles a portion of straw 

 two or three inches in length, from the orifice of 

 which protrude the polype, with two circlets of ten- 

 tacles, one immediately surrounding themouth,the 

 other circlet lower down near a second aperture 

 or mouth communicating with the body enclosed 

 within the tube. 



Another form is presented by Tibiana, of which 

 Fig. 3842 shows the Tibiana fasciculata. In this 

 species the tube assumes a series of angular flexures, 

 each angle having an orifice for the piotiusion of 

 the polype. The tube is about as thick as a knitting- 

 needle, and numbers rise clustered together from a 

 common base. They are found in the Indian and 

 Australasian Seas. 



In the family Sertulariae we are generally pre- 



sented with beautiful frondescent zoophytes, (he 

 stem and branches being slender, horny, and appa- 

 rently jointed at regular intervals, each joint being 

 merely a break in the continuity of the sheath, 

 occasioned by periodical interruptions in its growth. 

 At the extremities, or along the sides of the 

 branches, are the cup-like cells of the polypes 

 arranged in a definite order: in some the cups are 

 sessile, that is, closely resting on the branch ; in 

 othera they are elevated on a stalk. In some spe- 

 cies of the genus Canipanularia the zoophyte grace- 

 fully twines around otiiers capable of supporting it, i 

 as the ivy round the oak, and sends up branches 

 crowned with a bell-like polype-cell having an in- j 

 dented margin. Fig. 3843 represents the Cam- i 

 panularia volubilis, of the natural size and mag- ' 

 nified. i 



In Thuiaria the cells are sessile and occupy each 

 side of the branches, alternatii>g with each other. 



In Sertularia the cells are also sessile, and ar- 

 ranged alternately or in paiis on the stem and 

 branches of the delicate frondescent polypary. 



In Plumularia (Aglaophenia, Lamour.) the cells 

 are arranged on one side of the small branches of 

 the horny arliculated penniforra polypary. In these 

 geneia the pohpary is fixed to shells or stones by 

 several tubular radical fibres. Fig. 3844 represents 

 Plumularia pluma (Sertularia pluma, Linn.). 



In Dynamena the cells are serrated, sessile, and 

 arranged in pairs regularly opposite, along the 

 branches and stem of a horny articulated plant-like 

 polypary. Fig. 3845 represents the Dynamena 

 operculala, from the Euiopean seas. It is attached 

 to stones by creeping radical fibres. 



In a group termed Polypiaria dubia by M. de 

 Blainville are arranged several forms belonging to 

 the Zoophyta Hydicida of Dr. Johnston, of which 

 one is the Piumatella. It seems probable that this 

 genus should be referred to the Bryozoa, with Ciis- 

 tatfclla and Alcyonella, &c. 



The genus Piumatella (Naisa, Lamour ) comprises 

 several fresh-water species, usually Ibund in clear 

 running streams, attached to the under surface of 

 the leaves of aquatic plants, as Nympha:'a, or to 

 stones in obscure recesses. The polypary is fixed 

 with a slender membranous stem, frequently rami- 

 fied, and both stem and branches terminated by a 

 polype capable of entire retraction within the 

 polypary. The mouth of the polype is surrounded 

 by tentacular cirrlii forming a horse-shoe figure. 

 Fig. 38^0 represents the Piumatella crisfata (Naisa 

 reptans, Lamour.) It is found in fresh water, and 

 the tubes are membranous, transparent, and branch- 

 ing, larger at the base than at the summit. We 

 shall conclude this part of our subject with a few 

 observations on the economy of the tubular horny 

 zoophytes. In these singular beings, so often mis- 

 taken for sea-weed, as the Tubularise, Sertulariae, 

 &c., the tubes are formed by the hardening of the 

 tegumentary membrane of the living pulp ; hence 

 we can easily conceive how it comes to pass that we 

 so often find the stems and branches laden with 

 vt sides larger than the cells (Figs. 3844, 38-15). 

 In these vesicles are developed the gemmules of a 

 succeeding race. When mature they escape by a 

 disruption of the top, or fall of the lid, and the 

 vesicles soon after wither and disappear. It is thus 

 that the Sertulariae and the allied zoophytes are 

 reproduced. The gemmules are provided with 

 minute cilia ; they row themselves about and ulti- 

 mately fix upon a congenial site, throwing out root- 

 like fibres after the manner of a plant. They then 

 push up a shoot, the commencement of a future 

 stem ; polype-cells and polypes are evolved on its 

 sides, branches are given off, and a cluster of polypes 

 connected by a living thread constitutes a family, 

 the objects and interests of which are identical, an 

 inscrutable instinct regulating all their workings. 

 The growth of these beautiful zoophytes is extremely 

 rapid, and their duration often short. Some appear 

 to have but a summer's existence, many are pro- 

 bably annual, and those which attach themselves to 

 sea-weeds cannot prolong their duration beyond 

 that of the frond upon which they are fixed. Those 

 which are rooted upon rocks, stones, and shells are 

 probably less perishable, and continue perhaps for 

 several years to develop new branches and new 

 polypes. 



\\ e may now turn to a higher order of zoophytes, 

 viz., the Zoartharia of M. de Blainville, the Fleshy 

 Polypes of some writers, the Zoophyta helianlhoida 

 of Dr. Johnston, of which the Actiniae, or Sea- 

 Anemones, are familiar examples. 



In these animals the body is regular, flower- 

 shaped, more or less elongated, and very contractile, 

 with a sac-shaped _ digestive apparatus, the oial 

 orifice being surrounded by tentacles variously 

 shaped and tubular; some are fixed, otheis are 

 free. 



In order to understand the general structure which 

 prevails in this section, let us examine one of the 

 Actiniae, which are common on the fide-covered 

 rocks of our coast or tenant the sandy shore. 



