COMMON FROG. 269 



PLATE III. 

 COMMON FROG (Rana lemporaria), 



Injected and dissected to show the chief features of the circulatory organs, and especially the 

 connected systems of the renal-portal and epigastric veins, together with certain portions of the 

 muscular system, the renal and reproductive organs. 



THE integument has been turned back on the right side, together with 

 the musculo-cutaneous vein, the superficial branches of which extend from 

 the knee to the shoulder ; part of the muscular wall of the body has been 

 removed on that side, but part has been left in sitti ; and the main trunk of 

 the musculo-cutaneous vein is seen crossing a slip which the obliquus 

 externus muscle receives from the scapula ; on the left side the muscular 

 and cutaneous elements of the wall have been turned back whilst remaining 

 in their natural connection with each other and with the epigastric vein ; 

 the shoulder girdle has been cut through the middle line, and fastened out 

 on either side so as to expose the lungs, heart, and great vessels ; the liver 

 has been removed with the exception of a small part of its substance, as 

 have also the stomach and intestines down to the lower end of the rectum. 



a. Intermandibular space. The skin is left in situ anteriorly in the sym- 



physial angle ; immediately posteriorly to its cut edge is seen part of 

 the mylohyoid or submaxillaris muscle ; and posteriorly again, and 

 at a deeper level, the converging hyoglossi in the middle line, and on 

 either side of them the geniohyoids. 



b. Tetradactyle hand. The first finger, i. e. second digit, or ' thumb ' so- 



called, has its basal joint more or less tumid in this, a male specimen. 



c. Muscles of thigh. The line points to the sartorius, which is bordered 



externally by the vastus internus, and internally by the adductores 

 and recti interni. See Ecker, Die Anatomic des Frosches, p. 115. 



d. Point where the musculo-cutaneous veins, constituted by factors from 



the regions of the head and face, but mainly from those of the back 

 and flanks, turn inwards to pass over a slip going from the scapula 

 to the external oblique muscle and join the subclavian vein. As the 

 skin is moist and glandular this vein has probably to a certain extent 

 a respiratory function. See Ecker, /. c., p. 88. 



e. Vein, called ' epigastric ' by Rathke, ' umbilical ' by Bojanus and Jour- 



dain, ' vena portae accessorial and ' vena abdominalis inferior s. an- 

 terior,' by other authors. This vein is mainly constituted by the 

 convergence of the two transverse branches from the femoral veins 

 seen at/" in the figure, but it receives twigs also from the abdominal 

 parietes, and a factor of especial significance in the shape of the 

 vesico-hemorrhoidal vein from the allantoid bladder and rectum. 



