TURSIO PERONII. 79 



seem to me to belong to this species. Oue of tlieui (No. 20) is ai)p;ir- 

 ently that mentioued by Schlegel uuder this species iu the Ahhandlungen 

 (Heft I, p. 24). It uiost resembles Frodelphinusfrocnatus. 



Judging from un authentic skull of i. horecdis in the National Museum 

 (presently to be described), I believe that there can be no reason tj 

 doubt the correctness of Professor Flower's identification of skull No. 

 3f)29 in the College of Surgeons. It is from Tasmania. The total length 

 is 44*^'". The triangular area iu front of the nares is but slightly con- 

 cave. The intermaxilhe, which are much depressed, do not touch iu 

 the median line; they are farthest apart at the distal extremity. The 

 central portion of the symphysis below is raised above the level of the 

 lower surface of the rami. The coronoid is high. The pterygoids, as 

 already stated, touch only at the tip. The palate is convex. 



All these characters are presented by the skull of L. borcaHs and are, 

 therefore, of no moment iu distinguishing the two species. Indeed, I am 

 at a loss to find cranial characters by which to distinguish them, since 

 the proportions of the two skulls (seep. 82) are on the whole very much 

 the same. In the skull of L. x)eronii^ however, the temporal fosste are 

 relatively smaller, the mandible is shorter, its depth opposite the coro- 

 noid process is less, and it is less attenuated at the extremity. The right 

 intermaxillary bone in our skull ot L. borealis ends proximall^^ opposite 

 the middle of the nares, instead of running back to the posterior wall, 

 but this is very probably an individual variation. 



The skull figured in the Osteograpkie is also mucli like that of L. bore- 

 alis from California, but we know that the former is from south of the 

 equator, while, so far as I am aware, no porpoise having the coloration 

 of X, borealis has been observed in southern waters. It would appear, 

 therefore, that the two species are closely alike iu cranial characteris- 

 tics, but widely dissimilar in coloration. 



The figures of L.peronii given by D'Orbigny and Gervais (specimens 

 from ('ape Horn) and Gray (specimens from midway between Cape Horn 

 and New Zealand) agree very closely, the chief difference being that 

 iu the former the pectoral liu is represented as dark in the center of the 

 posterior margin. 



Lesson's figure (Voyage of the Coquille, pi. 9, fig. 1) represents a dol- 

 phin with white flukes and an elongated beak, which characters are also 

 mentioned in the text.* 



This may be a distinct species, though it is more than probable that 

 the figure is inaccurate. The measurements of the exterior given by 

 Lesson t differ much from those which I find in the notes upon L. bore- 



Liii-ioL luuou iioui tuust; vviiiuu x nua in ii 



'Zoology, Voyage of the Coquille, i, pt. 1, p. 180. 



tX. c. 



