136 



ANIMAL PHYSIOLOGY. 



[LESSON 38. 



FIG. 223. 



The short oesophagus dilates slightly to form a very small crop 

 (e), which communicates with a true stomach of some length (d). 

 In this, as in the former instance, the true position of the pyloric 

 orifice is by no means clear, but, either into the stomach, or im- 

 mediately at the commencement of the intestine, the bile vessels 

 (g) empty their secretion. The canal terminates in a short colon 

 (e, f ). The head is shown at a, the antennae at b, and the rostrum 

 at k. 



619. The omnivorous Cockroaches (Blattaria) were erroneously 

 included in this order by Linnaeus ; they now form a distinct order, 

 under the name of Uictyoptera (diktos, to make lace ; pteron, wing). 

 The nutrimental organs present many points of great interest ; 

 the preparation from which the figure was made 

 (Fig. 223), remains connected to the head, 

 the parts of which it is not now necessary to 

 describe. The oesophagus (a) terminates in a 

 large crop (5), at the terminal portion of which, 

 eight (sometimes only six) large and strong 

 gastric teeth are found (Figs. 224 and 225). 

 The salivary glands are extensively developed 

 (c), and show a number of lobules terminating 

 in a lengthened sac, each gland communicating 

 with its proper duct. 



The crop has had a portion removed, to 

 show the structure and folds of the mucous 

 membrane; this is easily done, as the prepa- 

 ration is preserved in fluid. 



620. Immediately below the proventriculus 

 (gastric teeth), and at the commencement of 

 the stomach, there are eight long follicles disposed around it, usually 

 filled with a thick, white substance (d). These appendages in this 

 situation are peculiar ; whatever the nature of their secretion is un- 

 known ; but some authors suppose (with great probability consider- 

 ing the habits of the animal) that they are a second series of salivary 

 glands, pouring out their secretion on the food the instant it has 

 been duly and effectually comminuted by the gastric teeth. The 

 stomach (e) begins where the last described follicles connect, and is 

 a long, tortuous, convoluted tube, terminated by a distinct pylorus. 

 The Ileum (/) succeeds the stomach, and receives the contents of 

 the numerous short and slender biliary tubuli (g). 



The large distended colon joins the ileurn ; after one convolution 



Nutrimental organs, B. 

 Americana. 



