506 



TEGUMENTARY ORGANS. 



Calcareous deposits in the cnderon. Deposits 

 of this kind are very frequent in the Inverte- 

 brata. In the Pulmonate and some Gasteropod 

 Mollusks, for instance, globular masses of car- 

 bonate of lime are scattered through the en- 

 deron, and would almost seem to take the place 

 of fat. In nudibranchiate mollusks, such as the 

 Dorida3, spicula of like nature are met with, 

 and these sometimes unite into true internal 

 shells, as in the genus Villiersia. The greater 

 part of the skeleton of the Actinoid polypes, 

 and the whole of that of the Echinoderms, is 

 composed of calcareous networks of this kind, 

 and globular masses of calcareous matter are 

 scattered through theenderori of the Taeniadae, 

 though the clear spherical bodies observed in 

 these worms are by no means always of this 

 nature. Whether these ^nderonic calcareous 

 deposits ever take place in the Vertebrata ap- 

 pears to me to be, as I have said above, an 

 open question, only to be decided by a very 

 careful examination of the mode of growth 

 of their so-called "dermal" bones. 



BIBLIOGRAPHY. General Works. Heusinger, 

 Histologie. Quekett, Lectures on Histology. 



VERTEBRATA. Gurlt, Untersuchungen ttber die 

 hornigen Gebilde d. Menschen u. d. Haus-sauge- 

 thiere (Mliller s Archiv., 1836). Idem, Vergleichende 

 Untersuchungen tiber die Haut der Menschen und 

 d. Haus Saugethiere (Muller's Archiv., 1835). 

 Meyer, Haut d. Cetaceen. Meyer, Baa d. Haut 

 des Gurtelthieres (Muller's Archiv., 1848.) Eble, 

 Lehre von d. Haaren, (Consult also for the Hairs, 

 &c. the works cited in Henle's Allgemeine An- 

 atomie, and Kolliker's Mikroscopische Anatomic.) 

 Feathers : Dutrochet, Observations sur la Structure 

 et la Regeneration des Plumes (Journal de Physique, 

 Ixxxviii.). F. Cuvier, Observations sur la Structure 

 et Developpeinent des Plumes (Mem. du Museum, 

 xiii.). Michel, (in Reil's Archiv., xiii.). South, 

 Art. Zoology ( Encyclopaedia Metropolitana.) Scales 

 and integumentary organs of fishes. Leeuwenhoeck, 

 Arcana Naturae. Reaumur (Mem. de 1'Acad. Roy. 

 des Sciences, 1716). Mandl, Sur les Ecailles des 

 Poissons (Annales des Sciences Naturelles, 1839.). 

 Agassiz, Observations sur la Structure et le Mode 

 d'Accroissement des Ecailles des Poissons (Annales 

 des Sciences Naturelles, 1840 ; and Poissons fos- 

 siles, Vol. I.). Williamson, On the Microscopic 

 Structure of the Scales and Dermal Teeth of some 

 Ganoid and Placoid Fish (Phil. Trans. 1849). 

 Williamson, On the Structure and Development of 

 the Scales and Bones of Fishes (Phil. Trans. 1851). 

 Leydig, Histologische Bemerkungen ttber den Polyp- 

 terus bichir (Siebold und Kolliker's Zeitschrift, 

 1853). Leydig, Beitrage zur Mikroskopischen An- 

 atomic und Entwickelungs Gesehichte der Rochen 

 u. Haie, 1852. Leydig, Haut der Sttss-wasser Fische 

 (Siebold u. Kolliker's Zeitschrift, 1851). Leydig, 

 Schleim-kanale d. Knochenfische (Muller's Archiv., 

 1850). Peters, Report on the Memoirs of Mandl 

 and Agassiz (Muller's Archiv. p. ccix. 1841). Rathke, 

 Ueber die Beschaffenheit des Lederhaut bei Am- 

 phibien und Froschen (Muller's Archiv., 1847). 

 Czermak, Ueber die Haut Nerven des Frosches 

 (Muller's Archiv., 1849.) 



ANNULOSA. Lavalle, Annales des Sciences 

 Naturelles. Carpenter, Report on the Microscopic 

 Structure of Shells (Rep. Brit. Assoc. 184S). 

 Mayer, Ueber den Bau d. Hornschale der Kafer 

 (Muller's Archiv., 1842). Newport, On the Natural 

 History and Development of the Oil- beetle Meloe 

 (Linnaian Transactions, 1845-7). Leydig, Ueber 

 Argulus foliaceus (Siebold und Kolliker, Zeitsch, 

 B. II.). Leydig, Zur Anatomic von Piscicola geo- 



metrica (Zeitsch. I.). Let/dig, Ueber Artemia salina 

 und Branchipus stagnalis (Zeitsch. III.) Hollard, 

 Recherches sur les Oaracteres anatomiques des De- 

 pendances de la Peau chez les Animaux Articules 

 (Revue et Mag. de Zoologie, 1851). Meissner, 

 Beitrage zur Anatomic und Physiologic von Mermis 

 albicans (Siebold und Kolliker's Zeitschrift, 1853). 

 Quatrefages, numerous Memoirs in the Annales des 

 Sciences. 



MOLLUSCA. Poll, Testacea utriusque Sicilian, 

 1791. Gray, Some Observations on the Economy 

 of Molluscous Animals (Phil. Trans. 1833). Car- 

 penter, Report, &c. (Reports Brit. Assoc, 1845). 

 Leydig, Ueber Paludina vivipara (Siebold und Kol- 

 liker's Zeitschrift, 1850). Leydig, Anatomische 

 Bemerkungen ueber Carinaria, Firola, und Amphi- 

 ora (Zeitschrift, 1851). 



(T. H. Huxley.} 



RUMINANTIA (Lat. ruminare, to chew 

 the cud), Eng. Ruminants ; Fr. Ruminans ; 

 Ger. Wiederk'duende T/tiere, a well denned 

 order of mammalian quadrupeds, presenting 

 the following essential characters : Upper 

 jaw in nearly all cases destitute of incisor 

 teeth, their place being supplied by a callous 

 pad, while the lower jaw has six incisives ; 

 canines inconstant ; molars usually six on 

 each side of both jaws, with flattened crowns 

 surmounted by two double and irregularly 

 crescentic folds of enamel. Stomach com- 

 pound and divided into four cavities, so as 

 to provide for the ruminating act. Ccecum 

 large. Placenta generally in the form of 

 cotyledons. Feet ungulate and bisulcate. 



This order forms two natural divisions, 

 comprising the Hornless ruminants (akera- 

 tophora, Col. H. Smith) which are few in 

 number, and the Horned ruminants (kera- 

 tophora) which are very numerous. The 

 English naturalist Ray, who was the first to 

 propose a classification based on philosophical 

 principle, enumerated only fifteen species. 

 Pallas subsequently divided the entire family 

 into six genera, and the Baron Cuvier into 

 eight or nine; but the number of subdivisions 

 held to constitute genera by later authorities 

 has been very greatly extended. To serve 

 our present purpose we shall retain only 

 the Linnean and two other genera, which 

 may be conveniently arranged under the five 

 following heads or sub-orders : 



Camelus - 



\Auchenia - 



TMoschus - 



< Cervus 



(Camelopardalis 



f Antilope - 



| Catoblepas 



( Capra 



lOvis 

 Bovis 



The Camelidse differ in many important 

 particulars from the horned ruminants, and 

 exhibit an approximation to the Pachy- 

 dermata. The dental formula is peculiar; 

 thus in the genus Camelus there are, 



I. CAMELIDSE 



II. CERVID^E 



III. ANTILOPID^E - 



IV. (EGOSCERIDJE - 



V. BOVIDJE - 



Linn. 



Illiger. 



Linn. 



Linn. 



Linn. 



Linn. 



Smith. 



Linn. 



Linn. 



Linn. 



3 3 



1 1 



1 1 



3 3 



and in this respect the Auchenias, or Llamas, 

 disagree only in the number of molars, which 

 is usually fourteen. The distinguishing fea- 

 tures of this family depend principally upon 



