ON THE OUTLOOK OF VERTEBRATE MORPHOLOGY. 85 



posed by Krefft on analogy to Protopterus, making a 

 noble point in his observation that the period of low 

 water in the Burnet River is that of Ceratodus' reproduc- 

 tion. He draws the remarkable inference that although 

 the animal devours vegetable matter, it nourishes itself 

 upon the various small creatures associated therewith, 

 chiefly because he has observed the injested green food to 

 pass little, if at all, changed through the alimentary canal. 

 Concerning the functions of the lung-sac, he has made ex- 

 periments which lead him to the conclusion that that organ 

 is chiefly functional during respiration in bad or insuf- 

 ficient water, and the experiments show not a little analogy 

 to those of Day and others made upon Tropical Siluroids 

 and other fish already alluded to. It is unfortunate that 

 he should not have ascertained the results of complete 

 deprivation of access to the surface of clear water. 



Disposing briefly of the few observations made on 

 oviposition, the author proceeds to consider the external 

 phenomena of development, up to the time of first 

 appearance of the pelvic fins ; and furnishes in illustration 

 eight magnificent plates. Cleavage of the egg is total 

 and unequal, and comparable in important aspects to the 

 amphibian type. There is nothing in the development ot 

 the posterior nostril, as thus far observed, in any way 

 opposed to the supposition that it is homologous with 

 that of the terrestrial vertebrata. The first appearance 

 of end-organs upon and in the neighbourhood of the lateral 

 line in the form of papillate upgrowths appears of special 

 interest, in relation to Fritsch's discovery 73 of " spaltpa- 

 pillen " in the lateral line region of Elasmobranchs. The 

 pectoral fin is at first rounded in contour with a central 

 tapering axial lobe ; but with enlarging growth (as judged 

 by the drawings) it loses its regularity and assumes a 

 more angular and ordinary fish-like shape. 



There are no traces of either larval gills or suctorial 

 apparatus ; and the author, laying stress upon this, 

 controverts the view that the suctorial mouth of the 

 amphibian larva is a reminiscence of a cyclostome stage 

 in evolution. We most heartily agree with him. The 



