POLYTHALAMACEA POMATHORINUS. 



From this mass of evidence we collect in general, 

 that the varieties of bone, shell, coral, and the nume- 

 rous species of Polypidoms with which the last are 

 allied, only differ in composition by the nature and 

 quantity of the hardening or ossifying principle, and 

 by the state of the substance with which this prin- 

 ciple is mixed or connected ; the gluten or jelly which 

 cements the particles of phosphate or carbonate of 

 lime and the membrane, cartilage or horny substance 

 which serves as a basis, appearing to be only modi- 

 fications of the same substance, which progressively 

 graduates from a viscid liquid or gluten into a gela- 

 tinous substance ; this again by inspissation, and by 

 the more or less perfect degrees of organic arrange- 

 ment, forms the varieties of membrane, cartilage, and 

 horn, forming the peculiar differences of the several 

 species. 



In the matchless Museum of the Royal College of 

 Surgeons of London, several elegant preparations of 

 Madrepore and calcareous Polypidoms may be seen, 

 in which it is manifest that when the carbonate of 

 lime has been absorbed by a chemical operation, the 

 animal matter remains, still exhibiting its original 

 form ; but, being divested of its hardening matter, is a 

 mere gelatinous substance. 



Lamaroux has constituted four classes of flexible 

 Polypidoms, the 



FIRST CLASS is that of the celluliferous, whose 

 Polypi are found in shelly or non-irritable cells. It 

 is divided into three orders, beginning with that wi.ose 

 cells are apparently isolated, and comprehends the 

 Flustra, Ccllulana, \c. The second order includes all 

 those with coalescent or united cells, formerly styled 

 tiertularia; the Tubularia forms the third order, their 

 cells being tubular and horny, simple or branching, 

 with one or many openings. The 



SECOND CLASS, whose Polypidoms are styled cal- 

 ciferous, are of a chalky substance mixed with that of 

 animal, and continuing apparent in every stage ; this 

 rla*s also contains three orders, the lirst of which has, 

 like the Tubularia, the Polypi at the extremities of 

 the stems and branches, but, beinur less horny and 

 more calcareous, forms an intermediate link between 

 the last order of the first class and the second order 

 of the present class, whose Polypidoms are very cre- 

 taceous or chalky, but whose Polypi are not appa- 

 rent ; they are articulated, which distinguishes them 

 from the third order of this class, in which they are 

 not articulated. 



In concluding this article we are enabled to add, 

 that an able naturalist is about to publish, at no very 

 distant period, a systematic arrangement of these 

 \\onder-working creatures. It is a subject on which 

 more may be said, and less is hitherto known, than 

 any other ; but. the necessary information and obser- 

 vation is so difficult of access, that lew persons have 

 ventured to explore its mazes ; but the immense im- 

 petus now given to the study of nature by the united 

 labours of eminent men, in every part of the world, will 

 render her paths more easy to tread, and enable the 

 student to unlock the storehouse of her treasure. 



POLYTHALAMACEA, is the third order of 

 the first class, Ccphalopkora, of the French naturalists ; 

 it includes the genera, Orlhocerata, BelemniLes, Conu- 

 larin, Coiwlit.es, Orthoceras, and Baculiles ; these con- 

 stitute the tirst family, under the name of Ort/ioccrata. 

 The second family, Lituacea, includes the genera 

 Ictliiosarcolithcs, Lituo/a, Spirilla, Hamatites, and Am- 

 ' ratifa. The third family, Cristacea, comprise 



495 



the genera Crepidulina, Oreas, and Linthuris. The 

 fourth family, Ammonacea, includes the genera Dis- 

 eorbites, Scaphitcs, Ammonites, and Simplegas, The 

 fifth family, Nautilacca, consists of the genera Orbu- 

 liles, Nautilus, PolystomeUa, and Lenticidina. The 

 sixth family, Turbiuacca, includes the genera Cibicides 

 and liotalitcs ; and the seventh family, Turriculacea, 

 possesses only one genus, Turrilites. 



Under the different generic names a more full de- 

 scription is given of each of these molluscs, and it 

 will be seen that the greater number of them are only 

 known in a fossil state ; the most common recent 

 species, such as the Spinda and Nautilus, will give an 

 idea of the whole order, and why it has been called 

 many- chambered. The general characters of these shells 

 are, the body of the animal being contained more or 

 less in the last-formed division, the shell is straight, or 

 more or less rolled upon the same plane, divided by 

 chambers or septue, and these perforated with one or 

 more syphons or holes. The entire order is esta- 

 blished upon the imperfect knowledge possessed of 

 the animals of the Nautilus and Spirilla, to which 

 analogous reasoning approximates the other genera. 

 The arrangement of the genera constituting this order 

 has been guided by the curvature of the spiral cone, 

 the first straight, the others being gradually rolled 

 upon the same plane until no trace of it appears exter- 

 nallv, as in the Nautilus, 



POMADERRIS (Labillardiere). A genus of ever- 

 green shrubs from New Holland, having pentandrous 

 flowers, and belonging to Rhamnacccc. They are in 

 greenhouse collections, and are treated like other 

 plants from the same quarter of the world. 



POMATHORINUS, a genus of temdrostral, or 

 slender-billed birds, bearing some resemblance to the 

 sugar-eaters, but still sufficiently distinguished from 

 them to be reckoned a separate genus. The charac- 

 ters are : the bill long, slender, straight at the base, 

 but slightly bent towards the top, very much com- 

 pressed in the distal part, but without any notch, and 

 the culmen of the upper mandible with a distinct 

 ridge. The nostrils pierced obliquely near the base 

 of the bill, and partly covered by an oblong mem- 

 brane. The wings of moderate length and rounded ; 

 the tail long and also rounded. The feet with three 

 toes to the front and oue to the rear, the middle front 

 is the longest, but the hind one the stoutest of the 

 whole. The claws on all the toes much compressed, 

 crooked, and sharp at the points. All the known 

 species, of which there are several, are forest birds, 

 natives of the Eastern islands and Australia; but little 

 or nothing is known of their manners or their feed- 

 ing. The species first discovered were classed with 

 the bee-eaters, by the describers of the time ; but 

 they do not even belong to the same family, as the 

 bee-eaters have the feet syndactylic, and these birds 

 have not. 



P. temporalis was discovered in New Holland by 

 Brown, during Flinders' voyage, in the early part of 

 the present century ; but it most likely exists in other 

 parts of the east. Its length is about ten inches and 

 a quarter ; its tail pretty long, and its wings short. 

 The upper plumage is yellowish-ash, passing into 

 dull yellow on the under part. The front, under the 

 head, throat, and breast, are white, a thin line over 

 the eye and the tail-feathers are black, but the latter 

 have the tips white. The bill is black at the base, 

 and whitish at the top. 



P. superciliosus is another Australian species, for 



