14 PBCEEDINGS OP THE ACADEMY OF 



The scientific student will await with interest the receipt by our national 

 institution of further materials, so that the structure and affinities of these re- 

 markable beings may be fully made known. 



Part I. 



SYSTEMATIC SYNOPSIS 



Of the species of the Cetaceans of the West Coast of North America. By Prof. E. D. 

 Cope, Corresponding Secretary of the Academy of Natural Sciences of Fhiladel- 

 phia. 



CETACEA. 



Two sub-orders of this order are known to exist at the present period, which 

 differ as follows : 



Mtsticeti. 



Mandibular rami distinct from each other, without symphysis. Teeth none 

 in either jaw. A series of transverse corneous laminae on each side of the roof 

 of the mouth. 



Denticeti. 



Mandibular rami united distally by a symphysis. Teeth present in one or 

 both jaws. No corneous laminae in the mouth. 



I. MYSTICETE. 



There is but one family of this group, characterized as follows : 



Spiracles two. Front of cranium plane, much raised above the orbital pro- 

 cesses ; no transverse or longitudinal crest on the cranium Balsenidx. 



I. BALJENID^. 



Of this family numerous genera and species have been discovered and de- 

 scribed. It embraces the most gigantic of vertebrated animals, and some of 

 the most useful. They inhabit all oceans, but are rarer in the equatorial re- 

 gions, abounding most in the frigid and temperate seas. Their pursuit givea 

 occupation to many men of all nations. 



Owing to their vast bulk and the want of appreciation on the part of those 

 who are engaged in their capture, their study has been one of great difficulty. 

 It is only within a few years that a sufficiently extended amount of material 

 has been accumulated to enable the genera and species to be properly discrim- 

 inated. The works of Gray, Eschricht, Reinhardt, Lilljeborg, Van Beneden, 

 Flower and the writer, contain the most recent results of these investigations. 



The genera are as follows : 



I. Cervical vertebrae coossified ; fingers five. 



No dorsal fin or gular folds ; coracoid rudimental. 



Ribs single headed ^. Balxna. 



First rib double headed ..Ilunterius, 



II. Cervical vertebrae free ; fingers four. 



A. The throat without plicai ; no dorsal fin; ribs? single headed. 



No acromion Rhachianectet, 



An acromion Ayaphelus, 



B. Throat and breast plicate ; a dorsal hump or fin. 



a. The vertebral canal not closed by the processes of the cervical verte- 

 brae ; ribs single headed. 



No acromion Megaptera. 



A well developed acromion Eschrichtius, 



tta.. The canalis vertebralis enclosed by diapophyses and parapophysea 

 of cervical vertebrae; both acromion and coracoid. 



[April, 



