290 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



arises from the antero-dorsal region of the ganglion, 

 passes upwards, and fuses with the R. spinosus of the 

 nerve in front (third spinal). 



2. R. spinosus (r. sp. 4). — A motor ramus leaving 

 the postero-dorsal region of the ganglion, and giving oif 

 near its base a posterior lateral branch for the inter- 

 mediate portion of the dorsal musculature. It then 

 passes dorsally, and fuses with the R. communicans of the 

 nerve behind (fifth spinal). The resulting mixed trunk 

 continues upwards and forwards in the dorsal musculature 

 very close to the middle line, and is distributed to the 

 dorsal portion of the dorsal musculature, the inter-spinal 

 muscles and the dorsal skin. 



3. R. medius (r. m. 4). — This mixed ramus, leaving 

 the ventral extremity of the ganglion, courses laterally 

 outwards through the ventral portion of the dorsal muscu- 

 lature, and bifurcates. The upper division accompanies 

 the intermuscular bone, and supplies the ventral portion 

 of the dorsal musculature. The lower division passes 

 downwards into the lateral musculature (which it sup- 

 plies), obliquely crossing under the R. lateralis profundus 

 vagi (fig. 23, r. lat. prof . #.), to which it may be very 

 closely attached, but with which it never mingles. The 

 sensory fibres of the ramus pass out laterally to the skin, 

 and supply that portion of it around the lateral sensory 

 canal. 



4. R. yentralis (r. v. 4). — This mixed ramus also 

 arises from the ventral extremity of the ganglion, and is 

 the largest of all. It passes downwards, and just over the 

 kidney receives the R. communicans from the fourth 

 spinal sympathetic ganglion [com. iv.). It then turns out- 

 wards between the lateral musculature and the kidney, 

 and afterwards downwards again between the lateral 

 musculature and the liver. Finally it continues down- 



