1922] Allen, Congo Collection of Insectivora 31 



Cranial Variations. — Matschie 1 and others apparently believe 

 that the relative length of the frontal and nasal sutures is of specific value 

 in Rhynchocyon. Specimens of Rhynchocyon s. claudi in our series show that 

 the frontal suture may be as long as, or longer or shorter than, the nasal 

 suture, and in some cases one of the nasals is fully 4 mm. shorter than 

 the other. The following measurements 2 illustrate variations in speci- 

 mens taken in the same locality at Niapu: 







Frontal Suture 



Nasal Suture 



No. 49445 



c? 



24 mm. 



24 mm. 



49479 



9 



27.25 mm. 



19 mm. 



49443 



cf 



27 mm. 



20 mm. 



49459 



& 



28 mm. 



20.5 mm. 



49448 



& 



22 mm. 



25 mm. 



Rhynchocyon claudi Thomas and Wroughton was based originally 

 on a specimen in the light or reddish phase of coloration from Beritio, 

 near Angu, on the Uele River. Later a single specimen from Medje and 

 twelve others from Poko were referred to this species by Thomas. 

 The present collection contains 20 specimens taken at Medje, 5 col- 

 lected at Akenge, and 79 at Niapu. The two last-named localities 

 are within about thirty miles of Medje and Poko and have the same 

 environment. There can be little doubt therefore of the correct refer- 

 ence of all these specimens to R. s. claudi. 



Dentition of Rhynchocyon 

 Text Figure 1 

 The present large series of skulls of Rhynchocyon s. claudi affords 

 material fully disclosing the character of the dentition of Rhynchocyon 

 from its early stages to old age. In the youngest skull (No. 49434 — see 

 Table 4, p. 26) of the series the teeth are wholly enclosed in the gum; 

 in a slightly older specimen (No. 49427) the tips of the principal cusps 

 of the deciduous teeth (canines and premolars 2, 3, 4) have broken 

 through. Other specimens, more advanced, show the gradual develop- 

 ment of the milk teeth and the order of their displacement by permanent 

 teeth. In a succeeding table (Table 5, p. 28) measurements are given 

 to show the correlation of the size of the individual with tooth develop- 

 ment, from the stage just prior to the appearance of any of the teeth 



U893, Sitzber. Gesell. naturf. Freunde Berlin, p. 66. 



2 Other cranial variations are indirated in the tables of measurements and need not be especially 

 emphasized, as they present no unusual features. 



