NERVOUS SYSTEM. VERTBBRATA. i'.7 



EDENTATA. 



D. 775. The brain and spinal cord of an Armadillo (DaypuM sp.), 

 isolated. The cervical part of the cord is of considerable 

 thickness find scarcely swells at all at the point of < 

 of the brachial nerves. Between the bradual and h, 

 sacral plexuses, the cord is somewhat reduced in si/.e and 

 is slightly flattened from above downwards. The crural 

 swelling is of great length and not sharply detine.1. 

 cord is replaced posteriorly by a terminal filament and a 

 cauda equina. 0. C. 1358 R. 



D. 776. A similar specimen of the brain and spinal cord of a 

 Two-toed Sloth (Cholcepus didactylus). In its gem-nil 

 proportions this cord differs considerably from that !' 

 Dasypus, owing partly to the greater length of the thoracic 

 region of the vertebral column and the consequent backward 

 shifting of the lumbo-sacral plexus and crural enlargement, 

 and partly to the greater development of the limbs accom- 

 panied by a corresponding prominence of the limb-swelling. 

 The thoracic part of the cord is relatively very slender. 

 The crural swelling tapers abruptly behind to form the 

 terminal filament. 



In this specimen the nerve-roots, particularly in the 

 cervical and brachial regions, are very distinct. On either 

 side, a bristle has been passed along the cord between the 

 dorsal and ventral roots to demonstrate their divi-i.m. 

 towards the cord, into numerous delicate rootlets. The 

 ganglia on the dorsal roots are in many cases very clear. 



0. C. 1358 D. 



CAENIVOBA. 



D. 777. The hinder part of the spinal cord of a Lion (Fells leo), 

 injected. The dura mater has been divided along the dorsal 

 mid-line and reflected to either side, exposing the sub- 

 dural lymph-space and the delicate inner sheath of the cord 

 composed of arachnoid and vascular pia mater. Behind 

 the crural swelling, the cord rapidly diminishes and gives 



VOL. n. ^ K 



