2-iG REPORT — 1873. 



(as in Arcliegosaunis, Vrocordyhis, &c.). Moreover the scales are quite 

 imlilfe those of any well-established Labyrinthodont genus, and both in dis- 

 position and extent they are anomalous. The ribs and the (presumed) long 

 neck are also difficult to reconcile with the Labyrinthodont character of this 

 interesting fossil. 



As to form and size the scutes of the Labyrinthodonts vary much. They 

 may be oval, rhomboidal, lancet-shaped, or oat-shaped. They may be as much 

 as two inches long, or so minute as to be barely visible. "When thick and 

 large, they exhibit a cancellous bony structure in cross section ; in many cases 

 they are coated with an enamel-like layer ; and when the scute is very thin, 

 this layer seems to compose its entire substance. 



Such an armour cannot be exactly paralleled by any thing known among 

 recent Amphibia or Eeptilia. The CrocodiLia have bony scutes, which in 

 Caiman and Jacare lie along the belly ; but neither these, nor the bony scales 

 of certain lizards {Ophisaiirus, Pseudopus, Cj/clodiis), are restricted to the 

 ventral surface. The dermal ossifications of Chelonia are dorsal as well as 

 ventral. In a few recent Batrachia {Ceratophrys cornuta, G. ornaia, Brachy- 

 ceplialus epMppium*) there is a partial dorsal shield. In the cutis of some 

 Gymnophiona there are minute flexible scales f. 



Granular, shagreen -like scales have been found to cover other parts of the 

 body of a few Labyrinthodonts. Dr. Dawson has figured and described a 

 remarkable covering of homy scales as forming dorsal and lateral appendages 

 to Hylonomus Lyelli'^; but there does not appear to be conclusive evidence as 

 to their disposition. 



Nature of Food and Mode of Life. — The character of the teeth and the 

 striicture of the skull, so similar as a prehensile and masticatory organ to the 

 skulls of Crocodilia, indicate plainly that the Labyrinthodonts were predacious 

 animals. Patches of Acanthodian scales foxmd on the inner side of the ven- 

 tral armour have led Burmeister to suppose that Archegosaurus at least was 

 a fish-eater§. Von Meyer quotes instances of the occurrence of fragments 

 of Archcgosaurian plates in coprolites assigned to the same species. Dr. 

 Dawson has found near the bones of Hylonoiims portions of coprohte contain- 

 ing remains of insects and myriapods || ; while numerous bones of the same 

 Labyrinthodont genus occur in coprolitic masses attributed io Dcndrerpeton^ . 



The Amphibian affinities of Labyrinthodonts and the presence of a branchial 

 apparatus in the larva render it plain that these animals were wholly aquatic 

 in their earliest stages. The proportions of the skuU, and the weak limbs of 

 all the known Carboniferous species, at least, furnish reasons for beheving 

 that throughout life they frequented water, and sought their food in it. The 

 analogy of all other Amphibia would lead us to suppose that the Labyrintho- 

 donts were fluviatile, not marine. The character of the deposits in which 

 their remains are usually found confirms this view. 



There is ground for believing that the largest Labyrinthodonts attaiaed a 

 length of seven or eight feet, though accurate data are wanting. Some of 

 the smaller examples, though adult and perfect, do not exceed as many inches 

 in length. 



Zoological Affinity, — In the present state of palseontological knowledge it 



* Formed in this case by tlie dilated processes of six dorsal vertebrae. 

 t These arc wanting in Cacilia aimulata. 



X Acadian Geology, 2nd ed. pp. 372, 375, fig. 144 ; and restoration, p. 352. 

 Archcgosmmts, p. 60, t, iii. figs. 3, 4. Von Meyer regards this as doubtful (Eeptilien 

 &c. pp. 6, 7). 



II Acadian Geology, 2nd ed., p. 376. ^ Ibid. p. 379. 



