NATURAL SCIENCES OP PHILADELPHIA. 199 



are narrower, and the end of the muzzle more prolonged into an edentulous 

 beak than appears in Prof. Reinhardt's figure, in his memoir on Orea eras- 

 si d e n s. 



The triangle extends to opposite the posterior tooth ; the premaxillaries 

 below, to opposite the third from behind. At the latter point the width of 

 the intermaxillaries is double the width from their border to the plane of that 

 of the maxillaries, and it increases from that point to the end of the muzzle, 

 where they are rugose and decurved. Teeth JL, very strong, cylindrical, and 

 incurved, except the posterior superior, whicn is weak and straighter. 



W In. Lines- 

 Breadth of muzzle at notch 8 



" at fifth tooth 6 6 



" at anterior tooth 3 



Length from notch 12 8-8 



of ramus maudibuli from condyle 20 



of series of mandibular teeth 9 8 



" gonys 3 7 



Depth of ramus behind last tooth 2 9 



" " at coronoid process . 5 5 



Lagenorhynchus leucopleurus Gray. 



One cranium Mus. Academy, loc. unknown, with long styloid process and 

 deciduous maxillary teeth. m 



Iu Lines. 



Length from end of muzzle to occipital condyle 13 8 



" " to supraoccipital crest :. 11 6-8 



" " " to maxillary notch.... 6 11 



" of temporal fossa 2 8 



" of styloid bone 3 1-8 



Breadth at middle of muzzle ." 2 7 



" at notch 3 10 



of nasal meatus 2 1-4 



between postorbital processes 7 8 



" " temporal ridges " 6 5-8 



Teeth 27 



? 



Delphinus tursio, Fab. A half grown specimen, judging from the dis- 

 tinctness of the epiphyses. Though differing in various points from the 

 description of Cuvier, the most exact we possess, the peculiarities can be 

 mostly ascribed to immaturity. The specimen is complete, and is supposed, 

 with some degree of probability, to have been taken on our coast. 



Breadth of muzzle at notch, two and one-sixth times its length ; latter dis- 

 tance, five-ninths total length of cranium. Occiput fuller in profile than in 

 Cuvier's figure, and considerably broader when viewed from above : this 

 breadth enters length of cranium two and one-sixth times. Parasphenoid alas 

 not excessively prominent. Vertebra C. 7, D. 11, L. 22, to first pierced laterally; 

 C. 13. Eleven pairs of ribs. Cuvier gives D. 13, L. & C. 3S, and thirteen 

 pairs of ribs. It is evident that six vertebrae have not been lost from our 

 specimen, though some may be wanting, and possibly one pair of ribs : the 

 limit of variation in this respect among the dolphins is not known. 



Compared with Cuvier's figure, the diapophyses of the atlas are narrower and 

 more acuminate, and the superior and inferior processes of the fifth cervical 

 verteba-a less developed and convergent. The dorsal diapophyses are thinner, 

 and destitute of a marked anterior ridge. In the twelfth caudal the chevron 

 bone is as large as the neural spine in profile. The anterior sternal piece is 

 less emarginate and not laterally projecting in our specimen: the nosterior 



* K. Danske vid. Selskab. Forhandl. 1862, 101. 



1865.] 



