62 On the Osteology of Loxomma AUmanni. 



even approximately be estimated, in the absence of caudal 

 vertebrae. 



The ribs are long and strong and of reptilian type, showing 

 that the thorax was capacious, and that respiration must have 

 been vigorously carried on by means of diaphragm and lungs. 



As no scales or scutes have been found with the remains of 

 Loxomma^ the skin may have been soft ; perhaps further 

 researches may show that it had some defensive armour. 



On the whole we conclude that Loxomma Avas a rather 

 sluggish Reptile, capable, hoAvever, of vigorous movements, 

 and predacious, inhabiting the waters, swimming mostly 

 like a fish, but guided by its paddles, that it breathed air, 

 however, like the Alligators and Crocodiles of modern time. 

 It must find its place in the scale of animals somewhere 

 between Fishes and Reptiles — between the salamandroid fishes 

 and the Crocodilia ; for whilst it resembles most the Laby- 

 rinthodontia, it possesses characters, more or less important, 

 in common with all the orders lying between Ganocephala and 

 Crocodilia. 



It clearly links together, in a very remarkable manner, the 

 two great classes of Fishes and Reptiles, and adds fresh confir- 

 mation, if indeed such were needed, to the opinion of Professor 

 Owen that " other extinct orders (Ganocephala and Labyrin- 

 thodontia) have demonstrated the artificial nature of the 

 distinctions between fishes and reptiles, and the close transi- 

 tions that connect together all the cold-blooded vertebrates." 



EXPLANATION OF THE PLATES. 

 Plate IV. 

 Upper surface of cranium o^ Loxomma AUmanni, half the natural size. 

 P.max, premaxillai-y bone ; M.g, mucous gi-ooves ; A.n.o, ante- 

 rior nasal orifices ; N, nayal bones ; Max, maxillary bone ; L, 

 lacrymal ; Ji(, jugal; Qu.ju, quadrate jugal; Qti, quadrate; 

 S.t, supratemporal ; O.v, orbital vacuities ; Fr, frontal bone ; 

 Pr.fr, prefrontal ; Pt.fr, postfrontal ; Pt.o, post orbital ; P, pari- 

 etals, with parietal foramen ; Sq, squamous; >S'.o ?, supraoccipi- 

 tals, so-called; Mad, mastoid; T.f, temporal fossa; S.o, supra- 

 occipital; lEx.o, exoccipital. 



Plate V. 

 Under surface of cranium of Loxomma, half the natural size. P.max, 

 premaxiUary bone ; V.t, vomerine tusks ; P.jj.v. palate-plates of 

 vomers; P.p.p, palate-plates of palate-bones; P.p.inax, palate- 

 plates of maxillaries ; A.max, alveolar border of maxillary ; Ap, 

 apertui-e in palate ; P.t, palate-tusks ; Sect, section of this tooth 

 shown in Plate VII. fig. 5; Ju, jugal; Qit, quadrate; Pter, 

 pteiygoid ; i?, ridge on median line between palate and pterygoid 

 bones; Ec.pter, ectopterygoid ; B.sph, basisphenoid ; P.n.o, 

 posterior nasal orifices; B.oc, basioccipital ; Ar.cav, articular 

 cavity of ditto for atlas; F.e.voc, facets of exoccipital for arches 

 of atlas. 



