104 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



beyond the upper surface of the jaw, and in this respect as well as in the 

 larger size of the alveoli themselves, the specimen departs widely from 

 Anoplonassa. I cannot discover that Dr. Abel has given any informa- 

 tion regarding the depth of the mandible, but he states that the sym- 

 physis is short. In the figure which accompanies the description the 

 jaw is ^ wider at the line of the posterior end of the symphysis than im- 

 mediately behind the anterior alveoli. 



As regards the relations of Palaeoziphius scaldensis to Anoplonassa, 

 Dr. Abel remarks : — 



" The genus Anoplonassa, from the Phosphate Beds of Savannah (Georgia), 

 represents a phase of development in which the alveolar canals of the mandible 

 have become rudimentary, with two pairs of teeth [i. e., alveoli] close together ; 

 the anterior terminal pair is twice as large as the second pair, which is situated 

 at about the middle of the length of the symphysis. The jaw recalls that of 

 Squalodon in general form. 



" Although one may without hesitation unite Anoplonassa with the ziphioids, 

 until now those stages (of development) have been lacking which lead from Ano- 

 plonassa to the oldest polyodont and homodont ancestors of the ziphioids. This 

 intermediate form is now represented by the type that Du Bus has described 

 under the name of Chamsodelphis Scaldensis [= Palaeoziphius scaldensis (Abel)]. 



" In a comparison with Atioplonassa the agreement in size, the length of the 

 symphysis, and the upward inflection of the anterior extremity [of the mandible] 

 immediately strike the eye ; the jaw from the Antwerp Bolderien also recalls that 

 of Squalodon. But that which at once clearly distinguishes the Antwerp jaw 

 from that of the Phosphate Beds of Savannah, Georgia, is the presence of 14 alveoli 

 in each half of the symphysis." 1 



The foregoing quotation appears to indicate that Dr. Abel considers 

 Palaeoziphius the nearest known ally of Anoplonassa, and hence more 

 closely related to it than are Cetorhynchus or Mioziphius. The reasons 

 which induce him to assign Palaeoziphius to the Ziphiidae are not 

 stated in his paper, so far as I can discover, except as appears in the 

 comparison with Anoplonassa above quoted. The resemblances between 

 the two genera therein mentioned are : (1) the approximately equal 

 size, (2) the expansion of the end of the mandible, (3) its upturned 

 extremity. 



As already alluded to, the size of the mandible is somewhat larger in 

 Anoplonassa. The symphysis is certainly somewhat longer, and proba- 

 bly much longer. The expansion of the end of the mandible is much 

 greater ; indeed, in Palaeoziphius it is so slight as not to be appreciable 

 in the figure given by Dr. Abel. It is true that Anoplonassa has the 



i Loc. ciL, (1905), p. 92. 



