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AyyAL> XEW YORK ACADEMY OF >CIEXCE> 



Fig. 2. — Skull pattern of Oste^tlepis microlepidotus 



A primiiire Devonian rWpidistian. 



After Pander, but with revised identification of elements. 



A, Top view. B. Side view. 



Supposed homologies with the skull elements of Tetrapoda are indicated by the ab- 

 breviations. 



Dorsal series: Xa. naso-ethmoid region : F. frontal region with median foramen : Po.f., 

 postfrontals ; Pa, parietals ; bebind the parietals are the parieto-occipital series, perhaps 

 not differentiated in Tetrapoda, as they lack the occipital commissure of sensory pits 

 (see text). 



Cixcumorbital series: P.f. prefrontal: La, lacrymal : -/ii, jugal (suborbital) :Po.o, post- 

 orbital. 



Temporal series: S.t, supra temporal (pterotici ; Sq. squamosal (preopercultim, cheek 

 plate •■X">. 



G n a th al series: Mx, mayjlla (the prem axilla is not separated from the naso-ethmoid 

 mass I : QJ, quadratojugal (anterior interopercolum. cheek plate "X"" > ; D, dentary ; 

 .>p. splenial (anterior inf radentary » : Ang, angular i middle inf radentaries > . 



Opercular series (lost in Tetrapoda) : Op, operculum: S.op, suboperculum : Gu, gular: 

 I.op, interoperculum t ; may have fused with quadratojugal in Tetrapoda >. 



Nuchal-occipital series: D.*o, dermosupraoccipital • postparietal. median suoratemporal » : 

 Tb. tabulare (epiotic. lateral supratemporal*. 



