196 



NATURE 



[Dec. 27, 1888 



ciated ; and unfortunately the days cannot be very far 

 distant when economy in fuel will become even more 

 necessary than it is now. 



Siemens, as is well known, had greatly at heart the 

 subject of smoke abatement. He applied his principles 

 to the construction of domestic fires, which are the main 

 causes of smoke and fog in many of our large towns. 

 His improvements have not yet to any considerable ex- 

 tent been adopted, but it is greatly to be desired that 

 a reform in this direction should speedily be brought 

 about. 



To describe his labours in connection with the intro- 

 duction of the electric light, the electric furnace, electric 

 transmission of power, electric propulsion on railways, 

 would be quite beyond our limits. We can only refer our 

 readers to Mr. Pole's account of these subjects. The 

 necessary explanations are given with admirable clear- 

 ness, difficult as it is to compress them into moderate 

 limits ; and the book, in spite of our strictures at the com- 

 mencement of this notice, will be found full of instruction 

 and interest. 



SOME PALEOZOIC DIPNOAN FISHES. 

 Fauna der Gaskohle und der Kalksteine der Permfor7)ta- 

 tionBohmens. Band II. Heft 3, Die Lurchfische, Dipnoi, 

 nebst Bemerkungen iiber silurische und devonische 

 Lurchfische. Pp. 65-92, Pis. 71-80. "Von Anton 

 Fritsch. (Prag : in Commission bei Fr. Rivnl'., 18S8 ) 



ANOTHER part of Dr. Anton Fritsch's well-known 

 work upon the Vertebrate fauna of the Permian rocks 

 of Bohemia has lately appeared, and the description of the 

 fishes is thus commenced. The nature of the subject 

 does not admit of the introduction of so many novelties 

 as characterized some of the previous parts ; but the 

 interest and value of the work is fully sustained, and the 

 discussion of the characters of Ctenodus — the only known 

 Dipnoan fish of the Bohemian Gas-coal— is supplemented 

 by some remarks upon a few of its Palaeozoic allies, with 

 special reference to the supposed evidence of Dipnoans 

 from the Upper Silurian of Bohemia. In addition to the 

 ten beautifully-executed plates, the text is accompanied 

 by numerous woodcuts, and no less than ten of these re- 

 present illustrative fossils that are not Bohemian, while 

 six are devoted to important features in the skeletal 

 anatomy of the living Ceratodus. 



Dr. Fritsch commences by emphasizing the intimate 

 relationship existing between the genera Ctenodus and 

 Ceratodus; and each portion of the skeleton of the 

 Permian fish, so far as determinable, is then compared in 

 detail with the corresponding element in the existing 

 genus. The fossils, unfortunately, are for the most part 

 fragmentary, almost all the head-bones being scattered, 

 and none of the bones of the trunk and fins being dis- 

 covered in natural series ; but many can be identified 

 with considerable certainty when rigorously compared 

 according to the author's method. 



In the skull of Ctenodus there are several ossifications 

 in parts that remain permanently cartilaginous in Cera- 

 todus, and the dermal roof-bones are much more numerous 

 than in the last-named genus. A bone that was formerly 

 described as the pelvis of a Stegocephalian is now recog- 



nized as the squamosal of Ctenodus. There is no certain 

 evidence of maxillae and premaxillae ; and the mandible 

 exhibits possibly another feature of close agreement with 

 Ceratodus in the small size and scale-like character of- 

 the bone named dentary by Huxley. Dr. Fritsch con- 

 siders that the latter element is too insignificant to repre- 

 sent the dentary, and may thus be more appropriately 

 termed " dermomental " ; but his argument appears to us 

 far from satisfactory. 



An interesting point is remarked upon in connection 

 with the dentition of Ctenodus. The commonest of the 

 two species recognized at Kounovd was originally founded 

 upon the evidence of detached teeth, and named Cera- 

 todus barrandei, Fritsch ; but it is now identified with the 

 well-known English Coal-Measure species, C. obliquus, 

 Hancock and Atthey. The teeth vary so much in size and 

 so little in characters that Dr. Fritsch represents a series 

 to illustrate several stages in the life-history of the fish ; and 

 the small teeth named C. elegans, Hancock and Atthey, 

 thus appear to pertain merely to young individuals of 

 C. obliquus. 



Proceeding to a discussion of the axial skeleton of the 

 trunk, Dr. Fritsch fields evidence of the persistence of 

 the notochord, with the same arrangement of the neural 

 and hsmal arches as is met with in Ceratodus. In re- 

 gard to the parts of the appendicular skeleton, however, 

 satisfactory comparisons are as yet impossible ; though it 

 is considered likely that, in the pectoral arch, Ctenodus 

 exhibited a greater number of distinct elements than the 

 existing genus. 



The scales of Ctenodus are large, thin, and round, and 

 the outer surface of each " appears smooth in the middle, 

 and is only seen to be rugose when highly magnified. 

 The border exhibits concentric lines of growth, of varying 

 width, parallel to the margin. Across these extend small 

 parallel ridges, on the middle of which are rows of minute 

 pits, apparently indicating the spots that originally sup- 

 ported denticles." Another noteworthy feature is the 

 forked appearance of the sensory canal upon a detached 

 scale of the lateral line — a condition unknown in 

 Ceratodus. 



As the result of his researches. Dr. Fritsch concludes 

 that the Bohemian examples of Ctenodus obliquus must 

 have attained a length of about 140 centimetres. In every 

 part of the skeleton there is evidence of more complete 

 ossification than is observable in the existing Ceratodus; 

 and the occurrence of a greater number of dermal roof- 

 bones in the skull of Ctenodus as compared with that of 

 the living Dipnoan is a parallel case to that of the Am- 

 phibia previously discussed, — the Permian groups having 

 the skull better armoured than their allies at present 

 existing. 



After defining the teeth of a new species (C applanatus) 

 from the Gas-coal of Kounovd, and having also briefly 

 noticed another form (C trachylepis) known only by three 

 scales from Nyfan, Dr. Fritsch proceeds, in conclusion, to 

 treat of some of the remains of Dipnoan fishes met with in 

 the Devonian and Silurian, mostly of the Continent. A new 

 genus and species, Dipnoites perneri, is indicated by a 

 supposed head-bone from the Upper Silurian of the 

 neighbourhood of Prague. A new and more satisfactory 

 figure of the type-specimen of Gompholepis panderi, 

 Barrande, is next given ; and this, too, is regarded as 



