208 Field Columbian Museum — Geology, Vol. i. 



During middle Upper Cretaceous times the genus continued its 

 eastward migration. From India two or three of the primitive types 

 are reported. From the Pacific coast of North America one species 

 which -is very closely allied to the early forms has been discovered. 

 During middle Upper Cretaceous times came the introduction of the 

 waters of the great North American epicontinental sea, and with the 

 waters of this sea came in some of the primitive species from the 

 Western or Eastern waters. And here as in the epicontinental sea 

 of Europe conditions favorable to development were found. Bath- 

 mism here also found a strong ally in environment, and the result 

 was the production of thirteen or fourteen new species. But differ- 

 entiation of structure was of a greater degree. The development was 

 more accelerated and the changes more marked. The individual 

 grew to much larger size; nodes were developed where ribs only had 

 existed; the sutures became more complex and the form more globu- 

 lar. 



One remarkable fact in connection with the development of the 

 genus Scaphites is that its greatest development in both Europe and 

 America took place in a region lying between parallels 40° and 

 50 of latitude. This may be only a coincidence, or it may be that 

 when the paleontology of the now unknown regions is thoroughly 

 worked out the present conditions will be found to be only apparent 

 and not the real ones. If neither of these assumptions be correct 

 the explanation may be found to lie in the similarity of environ- 

 ments. 



The following is the distribution of the species of the genus 

 Scaphites. In Europe, S. (equalis, S. obliquus, S. texanus, S. conradi, 

 S. nicolleti, S. hippocrepis, S. hugardianus, S. ivanii, S. compressus, S. 

 conslrictus, S. culvieri, S. reiformis, S. geinitzi, S. inlatus, S. mul- 

 tinodosus, S. nodi/er, S. ornatus, S. quadrispinosus, S. tridens, S. tuber - 

 culatus, S. trinodosus, India, S. cequalis, S. obliquus, S. kingianus; 

 North America, S. warreni, S. conradi (3 varieties), S. larvceformis, 

 S. vermiformis, S. texanus, S. nodosus (3 varieties), S. mullanus, S. sub- 

 globosus, S. nicolleti, S. cheyennensis, S. abyssinus, S. iris, S. mandanen- 

 sis, S. hippocrepis, S. culvieri, S. quatsincensis, S. reniformis, S. semi- 

 costatus, S. vermiculus, S. verrucosus, S. comprimus. 



Ontogeny, Phylogeny and Paleontogeny. No description of the 

 ontogeny or phylogeny of the genus Scaphites has as yet been pub- 

 lished. As the adult forms of the majority of the species show evi- 

 dences of a degenerative character, it was supposed that the genus 

 was an abnormal type, and further that the individual did not per- 



