624 



POLYPI. 



fistulous; cells straight, filiform, tubular, distant, slightly 

 claviform, or spatulous, witli the openings placed laterally 

 below the summit. Fig. 46 u a magnified portion. 



CeUaria thuia. PI. 75, f. 47. Adherent, with the stem* 

 tabular and branched, sub-articulated, horny, shining, and 

 calcareous ; <vlU in rows, either concatenated, or aduate, or 

 iiu-rusted at the surface, fig. 48, a portion of a stem magni- 

 fied. European seas. 



I.iriozoa Caribeea. PI. 75, f. 49. Adherent, branched, 

 calcareous ; with tubular stems, jointed, creeping ; cells ob- 

 long, pedicellate, arranged in clusters of three, with apposite 

 clusters at the top of the joints. Fig. 50, a portion of a stem 

 magnified. West Indian sens. 



Serialaria lendigera. PI. 75, f. 51. Adherent, branched, 

 horny, stems slender, fistulous, provided with cylindrical 

 projecting cells, parallel, cohering in series, in masses, or in a 

 continuous spiral form. Fig. 52, a portion of a stem magni- 

 fied. European seas. 



Plumularia myriopliillum. PI. 75, f. 53. Adherent, 

 branched, horny, stalks slender, fistulous, simple, or branched, 

 provided with calyciferous ramuli : cells prominent, sessile, 

 dentiform, subaxillary ; vesicles subpedunculate. Fig. 54, a 

 portion of a stem magnified. European seas. 



Antennularia ramota. PI. 75, f. 55. Adherent, horny, 

 with the stems fistulous, simple, or branched, articulated, and 

 provided with verticillate, slender ramuli ; cells distant. Fig. 

 56, a portion of a stem magnified. European seas. Fig. 3. 



Sertularia fmteiceru. PI. 75, f. 10. Adherent, horny, 

 stems slender and fistulous, simple or branched, which, toge- 

 ther with the stems, are provided with separate, lateral, den- 

 tiform cells ; these are projecting, sessile, or subpediculated, 

 scattered, or disposed in two apposite rows ; vesicles larger 

 than the cells. Fig. 3, a portion of a stem magnified. Euro- 

 pean seaa. Serttdaria abietina, pi. 75, f. 73 and 77. 



CampanuFarta vertictllata. VI. 75, f. 57. Adherent, stems 

 fistulous, filiform, horny, simple, or branched; cells campanu- 

 late, dentated on the margin, supported by long, spiral foot- 

 stalks. Fig. 58, a magnified portion of a branch. 



Cormdaria. Adherent, horny, with simple funnel-shaped 

 stems, each containing a polypus ; polypus solitary, terminal, 

 mouth provided with eight tentacular pinnae set in a row. 



Tubula.ria.ra.mosa,. PI. 75, f. 59. Adherent, slender, tubu- 

 lar, simple, or branched, horny; points of the stems and 

 branches, each terminated by a polypus; mouth of the polypi 

 provided with two rows of naked tentacula, which are not 

 retractile, and with a varix at their origin. Fig. 60, a magni- 

 fied portion of a branch. British seas. Fig. 74, T. magnified. 

 Tropical seas. 



Plumatella. Adherent, slender, tubular, branching, sub- 

 raembranous, extremities of stems and branches terminated 

 each by a polypus; mouths retractile, provided with ciliated 

 tentacula, arranged in a single row, and destitute of a varix 

 at their origin. 



SECTION VII. 



Polypiferous masses either free, isolated, and floating in the 

 water, or adherent, anil agglomerated in cellular masses, 

 composed of one substance on aquatic bodies ; polypi pro- 

 vided with numerous tentacula, which do not complete the 

 circle round the mouth. The animals of this section chiefly 

 inhabit fresh water. 



AlcyoneUa. Incrusting, thick, convex, and irregular, con- 

 sisting of an aggregation of vertical subpentangular tubes, 

 open at their summit; polypi elongated, cylindrical, with 

 fifteen or twenty straight tentacu'a, disposed around the 

 month on one side, at the upper extremity. 



Spongilla. Adherent polymorphous, cellular, irregular, 

 composed of subpiliferous lamina 1 , forming unequal, diffuse, 

 irregularly disposed ceils, with gelatinous and free granules 

 within them. 



CrMateUa. Free, globular, gelatinous, covered by short, 

 thick, polypiferous tubercles, each of which encloses a polypus, 

 the extremity separated into two retractile branches, arcu- 

 ated and provided with pectinated tentacula; mouth situate 

 at the union of the tentacular branches. 



Difflugia. Body small, gelatinous, contractile, enclosed in 

 a testaceous tube, projecting; from one to ten tentacular 

 arms ; sheath oval, or subspiral, truncated, or open at the 

 base ; surface with agglutinated grains of sand. 



ORDER IV. POLYPI DENUDATI. 



Polypi provided with tentaeula, and not forming a polypi- 

 ferous mass ; greatly diversified in form, in the number and 

 situation of their tentacula, and fixed either constantly or 

 spontaneously. 



PediceUaria. Adherent, formed of a stiff peduncle, ter- 

 minated at the summit by a clavifbrm inflation, furnished with 

 scales, or radiated beards ; mouth terminal. 



Coryne. Fleshy, seated on a peduncle ; summit of a vesicular 

 club-form, provided with scattered tentacula; mouth terminal. 



Hydra viridit. PI. 75, f. 76. Oblong, linear, in the form 

 of a reversed cone, narrowed below, gelatinous, transparent, 

 nd fixed spontaneously by the base ; mouth terminal, pro- 

 v'idcd with a row of cirous tentacula. a. exhibits the body 

 extended, and 6. the body in a contracted state. Fig. 69, body 

 expanded. Inhabits fresh waters. 



ORDER V. POLYPI CILIATI. 



Mouth provided with ciliated and gyratory organs, which 

 agitate the water, but do not seize the food. 



SECTION I. ROTIFER!. 



With cue or many organs in a circular form, ciliated, and 

 rotatory at the opening of the mouth. 



Tubimlaria. Body contractile, oblong, contained in a 

 tube fixed on aquatic bodies ; mouth terminal, funnel-shaped, 

 proviileil with a retractile, ciliated, and rotatory organ. 



f'orticella polypina. PI. 75, f. 75. Body naked, pedunru- 

 lated, fixed spontaneously, or constantly by its base ; superior 

 extremity inflated, and terminated by a large mouth provided 

 with rotatory ciliae. Inhabits stagnant waters. 



Urceoltiria. Body free, contractile, urceolate, sometimes 

 elongated, without tail or peduncle ; mouth terminal, dilated, 

 provided with rotatory cihw. 



Furcularia. Body free, contractile, oblong, provided with 

 a short or elongated tail, terminated by two points or two 

 setae ; mouth furnished with one or two ciliated and rotatory 

 organs. 



tirachionut. Body free, contractile, nearly oval, covered, 

 at least partly, by a transparent sheath, stiff, capsular, and 

 provided anteriorly with one or two ciliated rotatory organs. 



Folliculina. Body contractile, oblong, im-losed in a trans- 

 parent sheath ; mouth large, terminal, with ciliated and rota- 

 tory organs. 



SECTION II VIBRATILES. 



Ciliae placed near the mouth, moving in interrupted vibra- 

 tions. 



Vaginicoli. Body minute, oval, or oblong, anteriorly 

 ciliated, and provided with a tail ; enclosed in a transverse 

 sheath, but not attached, 



Trichocerca. Body minute, oval, or oblor.g, anteriorly 

 truncated ; mouth retractile, sub-ciliated, tail forked, some- 

 times articulated. 



Rattulut. Body minute, oblong, truncated, or anteriorly 

 obtuse ; mouth distinct, tail very simple. 



POLYPUS, in medicine ; a name given to swell- 

 ings, which form chiefly in the mucous membranes, 

 and were considered to resemble the animal of the 

 same name. These tumours are most common in 

 the nostrils, the throat, the uterus, and are more 

 rarely found in the stomach, the intestines, the . 

 bladder, or the external passage of the ear. Poly- 

 puses differ much in size, number, mode of adhes- 

 ion, and nature. One species is called mucous, 

 soft, or vesicular polypuses, because their substance 

 is soft, spongy, vesicular, and, as it were, filled 

 with white juices ; another is called the hard 

 polypus, and has been distinguished into the fibrous 

 or fleshy, and the scirrhous or cancerous. The 

 fibrous polypuses are of a dense, close texture, and 

 of a whitish colour ; they contain few vessels, and 

 do not degenerate into cancers. The scirrhous or 

 carcinomatous polypuses are really cancerous, pain- 

 ful tumours, which discharge blood, and exhibit all 

 the pathological changes of cancerous affections. 

 Different modes of treatment must be adopted, ac- 

 cording to the particular nature of the disease. 

 Among the methods of cure are exsiccation, which 

 consists in subjecting the polypus to the action of 

 astringent powders or solutions, to effect the resol- 

 ution of the tumour ; cauterization, or the applica- 

 tion of fire and caustics ; excision, or the removal 

 of the polypus by the knife ; extraction, or its re- 

 moval by the fingers, or by pincers ; the seton, 

 which consists in the application of a wire or thread, 

 for the purpose of destroying the pedicle, or by 

 ligature, which consists in tying up the base of the 

 tumour, and causing it to fall off by the destruction 

 of the vascular pedicle which nourishes it. 



POLYTECHNICS ; used on the European con- 

 tinent, particularly in Germany, for the science of all 

 mechanical arts and skill, aided or unaided by 

 machinery. 



POLYTECHNIC SCHOOL in France, (Ecole 

 potytechnique) ; an establishment which ranks among 

 the first in the history of education. This school was 

 established by a decree of the national convention of 

 March 11, 1794, which was passed by the influence 

 of Monge, Carnot, Fourcroy, &c. The committee 

 of public safety had seen the necessity of providing 

 for the education of engineers. The school was 

 first called ecole centrale des travaux publics, which 

 name was changed a year after. Men like La 



