Karl Pearson and Adelaide G. Davin 
357 
Hylomys suillus dorsalis (see Plate XXIV, Figs. 62 a and 62?)) and RhyncJiocyon 
cerni (long-nosed jumping shrew). Two mounted specimens of the golden mole 
{Chrysochloris aurea) provided no signs of fahellae. A mounted specimen of 
Potamogale provided an external fabella, and a dissection of P. velox confirmed 
this. In Ericulns setusus we found no fahellae, but the cyamella and two anterior 
lunulae, an unusual combination. 
Plate XXIV, Fig. 59, provides a drawing of the lateral aspect of the left knee-joint 
of Potamogale velox. There was no sign of ossification in the popliteus tendon and 
only the external fabella was present. Fibula and tibia are fused at their 
distal ends. 
In Hylomys suillus dorsalis (Flate XXIV, Figs. 62 «. and 62 b) both fabellae are 
present and fibula and tibia are again distal ly fused. There was no cyamella, and no 
lunulae could be found. 
In the mole only the external fabella was present and there was no sign of 
ossification in the popliteal tendon. No lumilae could be discovered, but in such 
small animals absolute certainty could only be reached by cutting a series of sections 
of the semilunars. 
Parsons* in his paper on the limb myology of Gynnnira rafiesii notes the 
presence of an orthosesamoid in the external head of gastrocnemius ; he does not 
refer to the existence of lunulae ov cyamella. To sum up, the more primitive forms 
of the Insectivora probably possessed both fabellae, a cyamella, and mesial and 
lateral anterior lunulae. The external /o6e//a has been generally preserved, but the 
complete system as illustrated in the hedgehog shows signs of disappearance by the 
loss of one or more members as we also find in the higher Primates or Carnivores. It 
is, however, very far from being vestigial as in the case of the Chiroptera. 
(14) Rodents. 
According to Meckel the marmot, the common hamster, the guinea-pig, the 
agouti, the jerboa {Mus sagilta) and the hare have both fabellae, but the beaver, 
the squirrel, the rat, the dormouse and the Cape mouse (Aorychus capensis) only 
the external fabellaf. Bartolinus;!: had before Meckel referred to the two fabellae 
in the hare and Tyson to those in the guinea-pig. Owen§ found both fabellae in 
the squirrel as well as a lunula. He also found both fabellae in Mus rattus, the 
water vole (Arvicola amphibia), Hydromys chrysogaster (golden-bellied rat) and 
Hystrix cristata (common porcupine). Gruber made a fairly long investigation as 
to the fabellae in rodents. He found both fabellae in the following: Myoxus 
murinus (the fat dormouse), Sciurus vulgaris (connnon squirrel), external larger; 
Pteromys volans (? American flying squirrel), external larger; Tamias striatus 
(= Tamias asiaticus '^) ; Spermophilus citillus (European souslik) ; Mus musculus 
(common mouse); Mus rattus (common rat), external larger; Hypudaeus (1 Mus 
* Journal of Anatomij and Physiologii, 18'.(8, p. .322. 
t Loc. cit. S. 60J; — 5. + See Part I of this memoir, p. 147. 
§ Anatomy of Vertebrates, p. 384. 
Biometrika xiii 23 
