STRUCTURE OF THE SPLEEN IN REPTILES. 



349 



animal kingdom ; in the Ophidia and in the Saurians, the con- 

 stituent which in all other Vertebrata is chiefly developed, is 

 here rudimentary, whilst that which in the latter is an acces- 

 sory apparatus, agreeing with the cytogenous vascular sheaths 

 of the lymphatic and lymphoid glands, attains in the former its 

 greatest development. In consequence of this mode of develop- 

 ment, the spleen of these animals forms the link connecting the 

 lymphatic and lymphoid glands to the spleen of other verte- 

 brates. These peculiarities of structure justify us in proceed- 

 ing to describe the spleen of Ophidia and Saurians separately 

 from the remaining vertebrates. 



THE SPLEEN OF REPTILES. In Ophidia the spleen appears 

 to the naked eye as a granular mass, situated at the upper 



Fig. 64. 



Fig. 64. From the spleen of the Tropidonotus natrix. a, follicle, 

 with its capillary plexus ; b, septum -with venous plexus. 



extremity of the pancreas ; but in Mammals it lies on the left 

 side of the stomach, and presents a more homogeneous struc- 

 ture. It possesses a 1 capsule composed of fibrillar connective 

 tissue and fine elastic fibres. The interstices of the fibrils of the 

 connective tissue contain, especially in the middle layers of the 

 capsule, numerous lymph corpuscle-like cells. The deeper layers 

 exhibit, in preparations that have not been injected, regularly 



c c 2 



