194 THE FROG— THE PLATANA 



2. Make an incision in the body-wall, slightly to the right side of the 

 abdominal vein, which may then be seen clearly on the inner side of the body- 

 wall. Carefully detach this vein from the abdominal wall. Remove the skin 

 from the legs. 



Second Day 



Skeletal System (part). 



1. Remove the upper portions of the pectoralis muscles, covering the part 

 of the body between the arms, to show the bones and cartilages of the central 

 part of the shoulder girdle and sternum, viz. : 



(a) The thick coracoids. 



(b) The more slender clavicles anterior to the coracoids ; and both extend- 



ing, on each side, from the base of the arm towards the centre of the 

 body. 



(c) ITie sternum, consisting of a median row of cartilages which are believed 



to be derived from the shoulder girdle. It does not, therefore, corre- 

 spond to, or is not homologous with, the stemimi of the Pigeon or the 

 Rabbit, which is derived from the ribs. The sternum consists of the 

 following parts : — 



(i) The omosternum, consisting of two parts — viz. an anterior 

 cartilaginous part (sometimes called the epistertium) and a 

 posterior bony rod (the omosternum proper). 



(ii) The two cartilaginous epicoracoids. 



(iii) The metasternum, consisting of two parts — viz. an anterior 

 bony part (sometimes called the mesosternum or sternum) 

 and a posterior cartilaginous part (sometimes called the 

 xiphisternum). 



[In the Platana the sternum consists of the following parts : — 



(i) The two cartilaginous epicoracoids. 

 (ii) The metasternum, which is broad and consists of cartilage only.] 



Make a sketch of the pectoral girdle. {See Fig. 76, A or B, page 218.) 



2. Cut through the coracoids and clavicles on each side, close to the base of 

 the arm, and carefully remove this part of the pectoral girdle and sternum so as 

 to expose the heart lying beneath. 



Alimentary System. 



Make a sketch showing the heart, lungs, liver, gall-bladder, bile-duct 

 (common duct of liver and pancreas) going to the duodenum, exposed parts of 

 the stomach, duodenum, small intestine (or ileum), large intestine (or rectum), 

 pancreas, spleen, and urinary or cloacal bladder. 



