36 



SKELETONS AND SKULLS OF rRODELPHINVS—TRUE. vol. xvii. 



The last relationship, that of the number and portion of the metai)o. 

 phyes is, i^erhaps, of little importance, as these processes die away very 

 gradually and different observers might disagree as to the real number. 



In the number of phalanges. Dr. Liitken's two specimens show a con- 

 siderable difference, while those of Dr. Abbott agree well among them- 

 selves. The formulaj (the metacarpals being excluded) are as follows : * 



Digits. 



Finst digit . . 

 Second digit 

 Third digit. . 

 Fourth digit 

 Fifth digit-. 



36049, d". 1 36051, $. 



Phalanges. ' Phalanges. 



1 ' 1 

 8 i 8 

 5 5 



2 I 2 

 I 1 



36048, cf . 



Liitken's 

 No. 8, ? . 



Lutken's 

 No. 3. 



Phalanges. Phalanges. ' Phalanges. 



1 2 



8 (9) i 7 



5 6 5 



2 i 2 2 

 It 1 1 



The five skulls agree well in proportions, the rostrum being 00 to 61 

 per cent, of the total length in all. The breadth of the rostrum at its 

 base, compared with its length, varies from 37.5 per cent, in the largest 

 skull to 40.5 per cent, in the smallest. Other proportions may be learned 

 from the following table of measurements : 



Measurement. 



Total length from 

 ti]) of rostrum to 

 8iirf;i<i> of occip- 

 ital coiulyU'.s 



Length of ro.struni. 



Breadth of rostrum 

 at its base 



Length of temporal 

 fos.sa 



Vertical height of 

 temporal fossa. . . 



mm. 

 415 

 253 



95 



00 



47 



36049, r^, 

 Amiran- 

 tes Is- 

 lands. 



407 

 251 



95 



65 



50 



36051, ? , 



Provi- 

 dence Is- 

 land. 



inin. 

 403 

 244 



91 



64 



53 



36031, $,;36048, cf, 



Alphonse Johanna 



Island. Island. 



iiitn. 

 397 

 241 



96 



65 



56 



379 

 222 



90 



63 



54 



Liitken's Liitken's 



No. 8, ? . No. 3. 



mm. 

 400 

 245 



90 



Type of 

 P. attenu- 

 atus, Brit. 

 Mus. 3476. 



400 

 243 



383 

 229 



87 



65 



50 



The species P. attenimtus, (Gray), Avith which Dr. Abbott's specimens 

 are here identified, is one of a group of nominal si^ecies, thirteen or 

 more in number, which E regarded in my Revision of the Delphinidiet 

 as i^robably reducible to three. With P. attenuatus I associated Del- 

 phinus 2>seudodel2}Ms^Wiegimum;X Stow capensis, Gray •,^ nnd Clymene 

 punctata, Gray. || The first of these names, D. p.seu<lo(lelphis, appeared 

 originally as the legend of a plate in Schreber's Siiugethiere, represent- 

 ing a skull of the same general characteristics as those described herein. 

 No description (^f the type-skull has been published, so far as I am 



. * By referring to Dr. Liitkeu's illustrations I find that he apparently includes the 

 metacarpals with the phalange.s proper. In quoting his formuhe, therefore, I have 

 subtracted one from the number given for each digit. 



t Bull. U. S. Nat. Mus., No. 36, 1889. p. 67. 



t Schreber's Siiugethiere, pi. 358. 



§ Proc. Zool. Soc, Loudon, 1865, p. 522- 



II Loc. cit., p. 738. 



