872 MH. r. G. PARSo?rs on the [Nov. 29, 



the former runs to the index and medius, the latter to all four 

 digits. 



There is no trace of an Extensor Proprius Hallucis. 



The four Peroneal Muscles {longus, hrevis, quarti digiii, and quinti 

 digiti) have the attachments usually found in hystricomorphine 

 rodents. 



The outer head of the Gastrocnemius rises from the external 

 condyle and outer side of the patella ; a large fabella is developed 

 in it. The inner head only comes from the condyle and has a 

 smaller fabella. 



The Plantaris rises from the external fabella ; it is large and 

 fleshy in the calf ; its tendon with that of the gastrocnemius forms 

 the usual rope-like twisting described in the ' Journal of Anatomy ' 

 (vol. sxviii. p. 414). In the sole there is no muscular belly re- 

 presenting the flexor brevis digitorum, but tendons pass to form 

 flexoi'es perforati to all four digits, though the outermost is very 

 small. 



The Solem rises from the outer side of the head of the fibula ; it 

 joins the tendo Achillis just above the ankle. 



The Popliteiis is normal. 



The Flexor Tibialis (Flexor longus digitorum) rises from the 

 second quarter of the posterior surface of the tibia, below the 

 popliteus. It is inserted into the tibial tirssicle (see fig. 7, p. 877). 



The Flexor Fibularis (Flexor longus liallucis) rises fi-om the upper 

 half of the back of the tibia and fibula and sends tendons (flexores 

 perforantes) to all four toes. 



It will thus be seen that in Pedetes the flexor tibialis fails to join 

 the flexor fibularis in the sole. This is a marked contrast to the 

 arrangement in the Dipodidae and also to that of most of the 

 Hystricomorpha. 



The Tibialis Posticus and Accessorius are absent. 



The two middle Lumbricales are present. 



Of the deep muscles of the foot the first layer consists of an 

 adductor indicis and of an adductor minimi digiti. The second 

 layer contains four double-beaded flexores breves. The third layer 

 is represented by one dorsal interosseous muscle between the index 

 and medius ; it is inserted into the dorsal expansion of the medius. 



In contrasting the myology of Pedetes with my former work on 

 the muscles of other Eodents, it is evident that this animal, like the 

 Dipodidfe, occupies a position between the Hystricomorpha and 

 Myomorpha. The mostimportant Hystricomoi'phine characteristics 

 are : — 



1. The large anterior deep part of the masseter passing through 



the infraorbital foramen : this is always found in the 

 Hystricomorpha and never, so far as I know, in the Myo- 

 morpha except in a very rudimentary condition. 



2. The absence of the transversus mandibulae, which is always 



present in the Myomorpha. 



3. The absence of the omo-hyoid. It is true that this muscle is 



