PALEOZOOLOGIE ET PALEOPHYTOLOGIE y 



richthyids and the probable Semionotid will be described in the second 

 part of the same work, which is probable to be published rather soon. 



The Cestracionids, wich are described, are fragmentarely preserved being 

 in most cases represented merely by detached teeth and fm-spines. Valuable 

 informations with regard to the dentition and the jaws give, however, such 

 species as Acrodus Oppenheimeri and Palseobales polaris. 



The Ceraiodus species is represented by a fragment of a tooth, wich seems 

 to hâve much resembled those in C. Sturii and C. Kaupii. 



Cœlacanthids are shown to be very common in the Spitzbergen Triassic 

 and to occur with an imusually great variety of forms. Such species as 

 Wimania ? muliislriala attained a very considérable size, the jugular plates 

 for example measuring nearly 1/2 m. in length. Other forms as Aexlia, 

 Mylacanihiis and Sderacanthiis are developed with a typically tritoral 

 dentition consisting of spheroidal teeth. 



From anatomical point of view, certain of the Spitzbergen Cœlacanthids 

 are very well preserved with regard to the skull, and it thus has been possible 

 for the author to make several new observations, wich, in their turn, ma de 

 it necessary to give new interprétations of the homologies of many of the 

 bones. The course and position of the sensory canals could be traced rather 

 well and hâve been of great value for the understanding of the dermal bones 

 and the fusions of dermal bone-elements, wich undoubtedly has taken place. 

 After having given a summary of the organisation of the Cœlacanthids, the 

 author compares thèse fishes with the other Crossopterygians and then with 

 the Dipnoans, Actinopterygians and Tetrapods, arriving to the conclusion 

 that some primitive Rhipidistids may be the ancestors of the Cœlacanthids 

 or that the Cœlacanthids are developed from certain primitive, mainly 

 Rhipidistid-hke, Crossopterygians. Polypterus and Calamoichthys are sepa- 

 rated from, the real Crossopterygians and placed for themselves in the Order 

 Brachiopierygii between the order Crossoplerygii on one side and the Order 

 Adinopierygii on the other. 



The Palseoniscids are found to be represented by a rather great number 

 of species. The most remarkable among thèse is undoulîtedly Birgeria 

 Mougeoti, wich, so far as can be seen at présent, is closely related to or perhaps 

 identical with the so-called Saiirichthys Mougeoti of the description of 

 Agassiz and several other palseo-ichthyologues. In this species the primordial 

 neurocranium is partly very well known and in the main it has even been 

 possible to give interprétations of ail its foramina for nerves and vessels. 

 Moreover a very primitive, paired, myodome has been shown to exist and 

 several facts seem to indicate that a real trigeminofacialis-chamber was 

 developed. 



Boreosomus and Acrorhabdiis show several Catopterid-lïke characters and 

 differ from the other Palseoniscids also in the position of the dorsal fin far 

 forward above or partly anteriorly of the ventral fins. 



The Platysomids are very poorly preserved. Noteworthy is that Plalysomus 

 Nathorsii attained a very large size, its flank-scales sometimes being not less 

 than 85-90 mm. high. 



To the Family Calopîeridse the author refers the Gênera Catoptenis, Dic- 

 iyopyge, Colobodus s. sir., Perleidus, Dolloplems, and with hésitation Meri- 



