840 Olf THE ANATOMY OF PIPA AMEBIC AXA, [DeC. 3, 



The quadratus femoris is a small slender muscle, covered by 

 the biceps, exactly heneath which it lies. 



The accompanying d^a^^^ng (fig. 5) of the muscles visible in a 

 dissection of the outer side of the thigh shows two which I identify 

 with the pyrifonnis and ohdurator respectively. 



The semimemhranosus is a very stout muscle. 



The psoas is also well developed. 



I could not find a pectinevs, imless what I have called the 

 adductor brevis be really that muscle ? But I do not think, after 

 a comparison with Bana guppyi, that I have made this mistake. 

 The gastrocnemius is a very stout muscle, which arises by a 

 short strong tendon from the femur only. At the ankle it passes 

 into the strong sesamoid bone, well known in the Common Frog ; 

 perfectly continuous with the latter is a flat strap-shaped 

 tendon, which immediately divides into two divergent tendons, 

 which go to be inserted upon two cartilages which are attached 

 below the heads of the first and fifth metatarsals respectively. 

 The two tendons are united for their whole length by a thin tough 

 fascia. The two tendons and the uniting fascia apparently 

 correspond to the plantar fascia of the frog. But in Rana guppyi, 

 at any rate, the fascia is evenly stout throughout, and does not 

 strip ofE in the same way because muscles are attached to it. 



The tibialis posticus does not difier in essentials from Ecker's 

 account of that muscle in the Common Frog ; but neither in Pipa 

 nor in liana gupp>yi does the origin of the muscle extend along the 

 whole length of the tibia ; there is a considerable area at the upper 

 end free from it. 



The tibialis anticus also needs no comment, save that the 

 division into two bellies is higher up the leg than in Rana guppyi. 



The peroneus is well developed. 



So also is the extensor cruris ; both these muscles are much as 

 in Rana. 



The Jfexor tarsi anterior consists in Pipa of a stoutish muscle, 

 which arises from about the middle of the tibia. 



The flexor tarsi j^osterior has no extensor of the middle toe 

 attached to it as in Ratia. 



§ Summary of the principal Differences in the Musculature of 

 Pipa and Eana. 



The following muscles, which are present in Pipa, are wanting 

 in Rana : — (1) Pectoro-mandibular. (2) Abdominal portion of 

 latissimus dorsi. (3) Pulmono-cesophageal. 



The following muscles, which are present in Rana, are wanting 

 in Pipa: — {\) Rhomboideus. (2) Omohyoid. (3) Pectoro-cutaneus. 

 (■±) Sartonus. (5) Pecthum. (6) Branch of posterior extensor 

 tarsi to third toe. 



Other points of difference are : — 



(1) Origin of depressor mandibular from skull-wall in Pipa 

 instead of from fascia covering neck. (2) Small size of clavicular 



