1902,] ON THE YOUNG OF POLYPTERUS. 121 



large, whitish, especially at their edges. Arms and legs like sides ; 

 hands and feet heavily built, theii- upper surfaces greyish white ; 

 soles naked except under the heels. Tail but little bushy, its 

 haii'S broadly ringed with black and pale yellowish, their tips 

 whitish. 



Skull rather heaviei- than that of F. cepapi, Nasals broad, 

 expanded postei-iorly. Intei'orbital region broad, flat or slightly 

 concave ; postorbital processes well developed, projecting directly 

 outwards instead of backwards. Premolars y. Molars heavier 

 than in F. cej^api. 



Dimensions (approximate) of the type, measured in skin : — 

 Head and body 205 mm. ; tail 145 ; hind foot s. u. (wet) 41 ; ear 

 (wet) 19. 



Skull — henselion to basilar suture 28 ; nasals, length 12 "5, 

 least breadth 5, posterior breadth 6; interorbital breadth 12; 

 tip to tip of postorbital processes 1 9 ; intertemporal breadth 1 3 ; 

 palate length from henselion 18*5 ; diastema (to front of p^) 10*6 ; 

 length of tooth-row (omitting the small jo^) 8. Lower jaw, condyle 

 to incisor-tip 27"7. 



Hah. Muezo, near Lake Mweru. 



Tyjye. Old male. B.M. No. 2.1.6.8. 



It is diflicult to say to which species F. yulei is really most 

 closely allied. Externally it has a certain resemblance to F. annu- 

 latus, but that animal has only one upper premolar and differs in 

 many other details. From F. cepapi, found in the same region, 

 it is distinguished by its larger eai'S, grey instead of fulvous 

 limbs, whitish feet, larger molars, and other points both external 

 ani cranial. 



I have connected with this distinct Squirrel the name of 

 Mr. J. B. Yule, of the official staflf of the Protectorate, by whom 

 a large number of the North Nyasa specimens described now and 

 in former papers have been collected. 



4. On some Characters distinguishing the Young of various 

 Species of Polypterus. By G. A. BoulengeRj F.R.S. 



[Received January 28, 1902.] 



(Plates X. & XI.^) 



The increased interest which has lately been paid to the 

 remarkable African Crossopterygian Polypterus has resulted in a 

 better understanding of the characters by which the species can 

 be distinguished ^, and the recent exploration of the Congo has 

 added several forms, fully entitled to specific rank, which were 

 undescribed ^. 



1 For explanation of the Plates, see p. 125. 



2 cy. Boulenger, Ann. & Mag. N. H. (7) ii. 1898, p. 416. 



•* Cf. Boulenger, Poiss. du Bass, du Congo (190i), and Ann. Mus. Congo, Zool. ii. 

 (1902). 



