GRADIENTIA, namely the Urodela and Lizards. SERPENTIA, the Snakes and the Apoda. Brongniart, 1800, "Essay d'une classification naturelle des Reptiles,"[2] distinguishes:– CHELONII, SAURII, OPHIDII, BATRACHII; the last for the Frogs, Toads, and Newts. Latreille, 1804, "Nouveau Dict. Hist. Nat." xxiv.,[3] accepts the four Orders of Brongniart's "Reptiles," but clearly separates the fourth Order, "BATRACHII," from the rest by the following, now time-honoured, diagnosis: _Doigts des pattes n'ayant pas d'ongles; des branchies, du moins pendant un temps; des métamorphoses_. But there is not one word about "Amphibia" in opposition to "Reptilia." Duméril, 1806, "Zoologie analytique" (p. 90), and "Élémens de l'histoire naturelle," 1807, divides the "Reptiles batraciens," or "Batracii," into ECAUDATI and CAUDATI; he also introduces the terms "ANOURES" and "URODÈLES" as their equivalents; but since these terms appear in the French form purists do not admit their having any claim to recognition! Oppel, 1811, "Die Ordnungen, Familien und Gattungen der Reptilien," establishes the term APODA for the Coeciliae, and recognises their affinity to the Ecaudata and Caudata by removing them from the Snakes. De Blainville, 1816, "Prodrome d'une nouvelle distribution du règne animal"[4]– AMPHIBIENS SQUAMIFÈRES. [The Reptilia.] " NUDIPELLIFÈRES s. Ichthyoides. [The Amphibia.] {8}Merrem, 1820, "Tentamen systematis Amphibiorum." PHOLIDOTA. [The Reptilia.] BATRACHIA: _APODA_. _SALIENTIA_. { Mutabilia [with metamorphosis, _e.g._ _GRADIENTIA_ { Newts.] { Amphipneusta [Perennibranchiate Urodeles.] F. S. Leuckart, 1821, "Einiges ueber die fischartigen Amphibien."[5] MONOPNOA. [The Reptilia.] { with temporary gills: Ecaudata + Caudata pt. DIPNOA. [The Amphibia] { with permanent gills: "Proteidae," _Menopoma_ { and _Amphiuma_. Latreille, 1825, "Familles naturelles du règne animal." The Vertebrata are divided into _Haematherma_ and _Haemacryma_. These terms for warm and cold-blooded creatures were later on amended by Owen to _Haematotherma_ and _Haematocrya_. The latter are divided by Latreille as follows:– REPTILIA. Still including the Coeciliae amongst the Snakes. AMPHIBIA { Caducibranchiata. { Perennibranchiata. PISCES. Wagler, 1830, "Systema Amphibiorum." TESTUDINES, CROCODILI, LACERTAE, SERPENTES, ANGUES, COECILIAE, RANAE, ICHTHYODI. RANAE I. _AGLOSSA._ " II. _PHANEROGLOSSA_: 1. Cauda nulla. [The Anura.] " " 2. Cauda distincta. [The Salamandridae.] ICHTHYODI I. _ABRANCHIALES._ _Menopoma_ [_Cryptobranchus_] and _Amphiuma_. " II. _BRANCHIALES._ [The Perennibranchiate Urodela.]