78 DK CHAKLES J. PATTEN. 



Order Carnivora. 



Hearts of (a) Felis concolor, and 

 (b) Felis domestica. 



They occupy a mesial position within the thorax, so that the 

 mesial plane passes through the apex of the ventricles. The 

 ventricular portion of each is longer and narrower and the 

 apex more pointed than in the preceding groups. The antero- 

 posterior diameters greatly exceed the lateral. They lie behind 

 the third, fourth, fifth, sixth costal cartilages. 



The attachments of the pericardium to the diaphragm 

 resemble the condition found in the Eodcntia dissected, but the 

 membranous fold of connective tissue is less extensive in the 

 above Cariiivora. The attachments of the front of the peri- 

 cardium to the back of the sternum are more intimate in the 

 latter than in the former. In Felis concolor and Felis domestica 

 I also found that the outer or right border of the right auricle 

 and the margo acutus lie nearly in the one line, and only a 

 small area of the back of the ventricles near the apex touches 

 the diaphragm, the pericardium intervening. 



Order Primates. 



1. Hearts of Catarrhine apes : — 

 (a) Macacus innuus. 

 fb) Gynocephalus habuin. 



Position in the thorax slightly oblique. Therefore apex to 

 the left of the mesial plane. More so in the young than in the 

 adult. Heart rather shortened and broader proportionately in 

 the transverse direction than in the preceding order. 



The pericardium is not extensively attached to the diaphragm, 

 but a considerable area of it is spread out on that structure. 

 It follows from this, that more of the ventricular surface of 

 the heart is in relation to the diaphragm (the pericardium 

 intervening) than in the case of the preceding orders. This 

 surface of the ventricles is somewhat ^flattened, and marked off 

 indistinctly by a border from the back of the auricles. 



