62 A MANUAL OF ZOOLOGY 



The obturator has its origin on the symphysis of the 

 ischium and its entire lateral surface and is inserted 

 above the head of the femur. 



Muscles of the Leg — On the dorso-posterior surface 

 of the tibio-flbula note 'a large muscle, the gastrocnemius. 

 It has its origin by two heads passes around the calcan- 

 eum and is inserted in the fascia of the plantar surface 

 of the foot. This is the tendon of Achilles. The tibialis 

 posticus is a slender muscle between the tibalis anticus 

 an(i the gastrocnemius. It has its origin along the en- 

 tire inner surface of the tlbio-fibula, and is inserted on 

 the dorsal proximal end of the astragalus. The tibialis 

 anticus is a muscle opposite the gastrocnemius. It has its 

 origin on the femur near the knee joint, divides near the 

 middle of the leg, and is inserted by two tendons, one 

 on the astragalus and the other on the calcaneum. The 

 peroneus is a long muscle extending the *hole length 

 of the tibio-fibula between the tibialis anticus and the 

 gastrocnemius. Its origin is on the distal end of the fem-- 

 ur and it is inserted on the calcaneum. Between the 

 tibialis anticus and the tibialis posticus find a small muscle, 

 the flexor cruris brevis. Its origin is by a long tendon 

 which lies in a groove on the surface of the tibio-fibula. 

 It is inserted along the shaft of the tibio-fibula. The 

 smallest muscle of the leg is the flexor tarsi anterior. Its 

 prigin is on the anterior part of the distal half of the tibio- 

 flbula and its insertion is on the proximal end of the as- 

 tragalus. 



DIGESTIVE SYSTEM— The Buccal Cavity— Open the 

 mouth as wide as possible. Note the maxillary teeth on 

 the upper jaw, two smajl patches of teeth in the middle 

 line, the vomerine teeth. Look for two small holes later- 

 al to and slightly in front of the vomerine teeth, the 

 posterior nares. Is there any connection of the nostrils 

 and the posterior nares? In the posterior part of the 

 mouth two larger holes are found one on either side, the 

 eustachian tubes. What relation do these tubes have to 

 the tympanic cavity? Demonstrate with a bristle. How 

 do the eye balls effect the shape of tie roof of the mouth? 

 Are there any teeth on the lower floor of the mouth? 



