70 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 72 



tiilias, Mctopocetus, Cephalotropis, Rhegnopsis. It is apparent that 

 as regards most of them there is scarcely any reason for separation 

 from Plcsiocetus or Cctotherium or from recent genera, and that the 

 few which appear to be more pecuHar are so shghtly known that they 

 can scarcely be classified. True (The Genera of Fossil Whalebone 

 Whales allied to Balccnoptera, Smithsonian Misc. Coll., vol. 59, No. 6, 

 1912, pp. 1-8) who later went over the subject came in all essentials 

 to the same conclusion. 



Agriocetus is most likely a whalebone whale, but it is too slightly 

 known to be classified. It was described by Abel (1914, /. c, pp. 188- 

 194, pis. 4, 5, 7) from a very imperfect and indistinct skull from 

 Tertiary strata at Linz, referred to Squalodon by earlier authors. 

 Abel regards it as a near relative of Patriocetus, a step nearer to the 

 true whalebone whales. Only better discoveries will show whether 

 he is right or not. 



Perhaps Patriocetus belongs to the family Balcenidcs as it is under- 

 stood in the present work, but it is not sufficiently known to be 

 definitely placed. It was described by Abel (1914, /. c.) who has 

 given a full account of the history of the remnants in question. The 

 basis of the genus was partly some rather imperfect fragments which 

 previously had most often been referred to under the name Squalodon 

 ehrlichii, partly a quite well-preserved skull found later, all from 

 Tertiary strata at Linz. If Abel's interpretations and conjectures are 

 right he is no doubt correct in regarding Patriocetus as a precursor of 

 the true whalebone whales. Abel refers it to the Archseoceti, or at 

 least leaves the question undecided whether it actually belongs to 

 this group or to the Mystacoceti (Die vorzeitl. Sauget., 1914, p. 88) ; 

 most probably it should be regarded as a whalebone whale, a Balasnid 

 with the dentition still functional. But there is reason for doubt 

 about certain details in Abel's account. 



Patriocetus has in the skull a remarkably strong resemblance to 

 Agorophius, a resemblance that was seen by Brandt (1873, /. c, 

 p. 324) although the remains then at hand were rather insignificant; 

 and Agorophius belongs incontestably to the series of toothed whales 

 as a near relative of Squalodon. The peculiarity which places Agor- 

 ophius among the Odontoceti in opposition to the Mystacoceti is that 

 the maxillary bone pushes itself posteriorly as a thin limina over the 

 supraorbital process of the frontal, but does not stop in front of it, 

 or push itself in under it, or content itself with also covering it with 

 a narrow margin anteriorly. According to the great resemblances 

 which are found otherwise between the skulls of Agorophius and 



