4IO 



DA VI SON. 



EXPLANATIONS OF PLATES XXXIII AND XXIV. 



Fig. I. Dorsal aspect of Amphiuma's skull, X 2. P, premaxillary ; «, nasal; 

 tn, maxillary; /, frontal; //, parietal; // prefontal; q, quadrate. 



Fig. 2. /, premaxillary; vi, maxillary ; /^Z, parasphenoid ; /i^, pterygoid; q, 

 quadrate ; st, stapes ; a, exit for ninth and tenth nerves. 



Fig. 3. Lateral view of premaxillary with nasal, maxillary, prefrontal, and 

 portion of frontal removed, X 2. a, brain cavity ; g, frontal bone ; //, canal for 

 exit of olfactory nerve ; /, nasal septum of premaxillary ; /', a break in the septum. 



Fig. 4. Dorsal muscles of head, f, pterygo-maxillaris ; h, masseter ; i, cer- 

 vico-parietalis ; d, e, temporo-cervical tendons ; a, frontal bone ; g, prootic. 



Fig. 5. Muscles on dorsal aspect of posterior limb, c, femur ; a, rectus fe- 

 moris; e, ilio-peroneal. 



Fig. 6. Muscles on ventral aspect of posterior limb, c, adductor magnus; 

 e, gracilis ; a, inscriptiones tendineae. 



Fig. 7. Great adductor muscle of posterior limb, d, femur; h, tibia ; a, car- 

 tilaginous plate ; e, trochanter ; g, pectineus ; l>, ossified disc ; c, pubo-tibialis. 



Fig. 8. Transverse section of adult at the fortieth vertebra, a, left side ; 

 i, transversalis-abdominis ; h, obliquus internus ; g, obliquus externus ; k, fascia ; 

 e, fascia split from external envelope. 



Fig. 9. Incision through right body wall and both walls reflected. /, lateral 

 fascia line ; c, muscular cones. 



Fig. id. The three rows of cones seen when the skin and fascia are removed 

 from right side of Amphiuma. b, triangular rod of fat lying above the vertebrae ; 

 c, tendinous cord connecting apices of cones ; a, fascia of cone reflected to form 

 an inscriptio tendinea. 



Fig. II. Vent of the female longitudinally split open, f, capillary tubes ; b, 

 folds of membrane ; a, entrance to the oviduct; d, lip of vent. 



P'ig. 12. Young Amphiuma, 78 mm. X ij^. a, gill opening. 



Fig. 13. Ilyoid apparatus of adult. ^, epibranchialis ; ^, cerato-branchial ; 

 c, basibranchial ; d, basihyal. 



Fig. 14. Brain of young Amphiuma seventy-two millimetres long, a, b, pros- 

 encephalon ; c, mesencephalon ; d, metencephalon ; e, spinal chord. 



Fig. 1 5. Transverse section of the optic region of young Amphiuma sixty- 

 eight millimetres long, d, eye ; r, retina ; o, orbitosphenoid ; /, parasphenoid ; 

 /, atrophied tentacular canal; e, degenerated gland; a, brain; m, ramus; «, 

 Meckel's cartilage ; h, i, k, hyoid apparatus. 



