Tin: I'.ATKAC'lllA OF NOUTM AMHKICA. 



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lidj;*^ iiidicati's, liiuls its comjilotost (levelopiiieiit in the oxtinct j»omi.s 

 Latonia, i-stablislRMl by Von i\Ieyor on the L. scif/rietli IVoni the Miocene 

 olOeninj^en. A species also occnra in tlie fresh-water deposits of San- 

 van (//. riifiosK], whose sahnnandei-like vertebra' have been noticed 

 l»y (lervais.* Tliese animals. were nearly related to Discofjlossns, and 

 iiad, like it, short posteriorly directed processes on the ribs, as in the 

 ncnns Salaniandra. They were, however, inncli larger, had the I'ronto- 

 piirietal Itoiics completely ossified, and the whole of tlu^ craninm 

 roijilicncd externally by a dermo-ossilication. On this acconnt the 

 jit'Mus has been compared with Ceratophrys, which belonj;s to the 

 family of Cysti.unathida". 



In the reniainiiij^' and recent jnenera the strncture of the sternum is 

 worthy of noli'. In old individuals of Disco^lossus it is sometimes tibro- 

 cartilaulMoiis, as in IMpii. The sternum, hoinolo;;(»ns with the sternum of 

 the i^act'rlilia. rcscndih's the united ha'mapopliysial cartila.i;es of ihe an- 

 tciior ribs. In tin' ucnera in (piestion + this part is divided nearly up 

 tt» the i»oint of attachment to that precedinj;", each moiety beiiij;' directed 

 outwards ami backwards, and tapering into a lateral linea semiluuiiris. 

 iJelwecM tlu'Nc and the pnlu's there arc in Discojilossns the usual thice 

 pairs of linca- semilunares, connected on the median line by a stronj; 

 I'uca alba 



In Disco^lossus the prefrontalia are strongly developetl, bcinj; in 

 contact tor most of thcii' length, soiuctimes touching; the fronto- 

 parictaiia. In Alylcs tlicy are also in contact throuj;hout, but ai»' 

 transvcise and do not reach the frontoparietals; the fontanelle is 

 lar;;cr. and llic ril»s withtmt processes; the whole animal is weaker. 

 In this !^i ntis, as well as the preceding'', tin' i)upii is a vi'rtical slit; 

 cIscwIk rr found in Ilylorhiiui, I'latyplcctrum, Limnomediisa, i'elody- 

 tida' and Ilic Scaphi<»pida'. A species (.1. friisclicni)^ has left its re- 

 mains ill tiie Miocene Ibauidcohle along with I'ala'obatrachus. Mom- 

 liinaloi is similar to Alytcs in its osseous structure, except that the 

 prclVoiiialia are in contact anteriorly only, and that the sacrum i>i'<s 

 scnts liiil one condyle for the articulation of the coccyx, as is typical 

 of the Astcropliiydida' ami Aglossa. Along with Alyt«'s and Xen- 

 opus it has true ossa nasalia, which bound the external nares exte- 

 riorly, iliiis explaining their anonndous jiosition in llreviceps. where 

 they aie iiifeiioi. In ISombinator there is no caviim tympani ov auricu- 

 lar ossicles, and the tuba' Kustachii are rudiim'utary or wanting. This 

 character is said l»y Tschudi and llruch not to be exceptionless in 

 adiilis, and that the tiil)ic and tympanum are always present in Ihe 

 \ouiig ol bdtli iliis genus ami I'elobates. All European, except Lio- 



' r:iiii'iiiili)iit;:i<' I'laiivaisi', p. I'.H. 



t ihinr^ li:is i;i\ •11 it liu;Mri' "f it ill />'iii/i//iH((/ii)'. I'l. li, lij;. '.'I. 



I (!<i|>i', .loiini. Ai'.iil. I'liihi., I'i'iii, )•. T.'i. Ii'iiiiii ini^i-liilii ^ Von Meyer, r;iIii'i)iito,i;i'iiii!i- 

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