VISCERAL ANATOMY. 45 



The digestive tract itself is very simple. The walls of the oesonliagus, 

 as it enters the stoniacli, are thrown into about eight longitudinal coi-rugations 

 tliat I)ecome confluent in ])art witli the more numerous rugae of the lining of 

 the stomacli. These latter consist of about IG deep ridges and more numerous 

 shallow ones, running longitudinally. They become reduced to five or six 

 thickened folds at the pylorus, where they end. 



The stomach (Plate 9, fig. 7) in its undistended condition, is subglobular and 

 somewhat produced at the jiyloric end as in Gymnura, though not to the extent 

 figured by Dobson for Erinaceus. The cardiac pi^rtion shows no such extension 

 as in Erinaceus europeus. Peters has figured the stomach of Solenodon cubanus 

 as a nearly globular organ with tlie pyloms very nvar the oesophagus. This 

 is sojnewhat different fi-om its ai^jiearance in S. jxinuhKnis when undistended, 

 and may not represent its true forni. The greatest length of the stomach is 

 about 37 mm., and the cardiac l)readth about 25 mm. 



The small intestine merges with the large intestine so gradually that it is not 

 possible to tell definitely where the two meet, but the thicker-walled portion 

 f(jllowing the last of the Peyei-'s patches is here taken to be the large intestine. 

 The total length of the intestine from the pylorus is about 1390 mm., or nearly 

 four and one half times the length from the tip of the nose to the anus. In 

 Gymnura it is about six times the length of head and body. The total length of 

 the small intestine, from the jiylorus to the last Peyer's patch is 1200 nun., 

 and the large intestine 190 mm. There is no indication of a caecum. The wall 

 of the sniall intestine is seen under a lens to be thickly covered with \illi which 

 are arranged in more or less transverse zig-zag lines. There are some seven 

 Pej'er's patches. The first is oval, about S by 5 nun., and situated 132 mm. from 

 the pyloms. At about 185 mm. after this are two smaller patches, one behind 

 the other. A fourth about 14 by S nun., is found some 205 mm. jiosteriorly; a 

 fifth after 250 mm. more, and a sixth, 11 by 5 nmi. after 220 mm. The seventh 

 and last is a large one about 1200 nun. from the jiylorus. 



The course of the intestine from the ])yloi'us is back along the riglit body 

 wall for about 50 mm., then across to the left side, and thence again posteriorly 

 for some 25 mm., after which it turns ventrally and becomes nuich convoluted 

 in the lower abdominal region. It then passes forward along the left side of 

 the body and is again much convoluted below the stomach, whence the large 

 intestine, after a short curve ("transverse colon") runs directly back along the 

 dorsal l^ody wall to the anus. 



The structure of the liver (Plate 9, figs. 3, 10) is comixiratively simple. The 



