SUBORDER c MrSTACOCETI 87 



Temporal fossae uncovered, cranium slightly rounded, supraoccipital rather square. 

 Cervical vertebrae distinct. Dorsal, lumbar and caudcd vertebrae are long. Front 

 ribs two-headed. 



Subfamily 1. Argyrocetinae. 



Skull rather flat. Frontals expanded over the top of the cranium. Rostrum 

 very long. Teeth unusually numerous; those in front pointed, those in the rear conical. 



Cyrtodelphis Abel (Cha7npsodelphis Gerv.). Abundant in the European 

 Miocene. C. sulcatus Gerv. sp. 



Argyrocetus, Pontivaga and Isclujrorhynchus Ameghino and Saurodelphis 

 Burmeister. In the Miocene and Pliocene of Argentina. 



Subfamily 2. Acrodelphinae. 



Skull flat, frontals narrow, rostrum long and teeth with small serrations. 



Acrodelphis Abel (Champ sodelphis Brandt, Gerv., p.p. ; Phocaenopsis du 

 Bus ; Delphinodon Cope). Very abundant in the Miocene of Europe. 



An almost complete skeleton of Heterodelphis leionodontiis Papp was found 

 in the Miocene (Leita Limestone) of the Sopron County of Hungary. 



Priscodelphimis Leidy. PJiabdosteus, Lophocetus, Zarhachis, Ixacanthus Cope. 

 Miocene of North America. 



The subfamilies of Iniinae and Beluginae are not known as fossils. The 

 former contains the long-snouted genera Platanista, Inia, Pontistes and Pontoporia, 

 which only attain the length of 1 to 2 m., and inhabit the mouths of large 

 rivers. The latter consists of the short-snouted genera Beluga and Monodon. 



Family 5. Delphinidae Flower. 



Short snout, premaxillary without teeth and surrounded by the maxilla. 

 Upper and lower jaw have a varying number of conical, one -rooted teeth. The 

 symphysis of the loioer jaw is short. Orbits moderate. The anterior cervical vertebrae 

 are fused. Front ribs have two heads. 



The dolphins, in the modern fauna, comprise the largest number of forms 

 of the Odontoceti. The many genera of this family are found in all seas and 

 frequently inhabit also the mouths of large rivers. Fossil remains occur 

 sparingly in the Miocene, Pliocene and Pleistocene of Europe and America 

 and are referable to the modern Delphinus Linn., Steno Gray, Tursiops Gervais 

 (Fig. 109), Orca Gray, Pseudorca Reinh. and Globicephalus Lesson (Fig. 110), as 

 well as to certain extinct genera. Protophocaena Abel occurs in the Miocene of 

 Belgium, Palaeophocaena Abel is known from the Crimea, and Delphinopsis 

 freyeri Joh. Miiller with dermal ossicles is found in Croatia. All of these 

 belong to the Phocaenini. Pithanodelphis Abel, a dolphin, has been described 

 from the Miocene of Belgium. 



Suborder C. MYSTACOCETI. Whalebone Whales. 



Skull symmetrical. Nasals short and overhanging to a certain extent the two blow- 

 holes. Functional teeth lacking. Upper jaw provided with whalebone and very broad 

 posteriorly, but not p)rojecting over the frontals. Lachrymal bones small. Mandibular 

 extremities not meeting in a symphysis, hut separated and slightly convex. Almost all 



