BLOOD-VESSELS OF MUSTELUS ANTARCTICUS. 
729 
figure) and the veins on the left ; the precaval sinus has its ventral wall 
removed. 
Fig. 3. The vessels in connexion with the cloaca and adjacent parts ; from the left 
side (nat. size). 
Clo., cloaca ; Kcl., left kidney ; Beet., rectum ; Beet, gl., rectal gland ; Ov., 
ovary; Ovd., left oviduct. 
Fig. 4. The heart; from the right side (nat. size). 
Fig. 5. Transverse section of the second holobranch (nat. size). 
Br. jU., branchial filaments ; Be. r., cartilaginous branchial ray ; C. hr., 
cerato - branchial; Ex. br., extra-branchial; M. ep. e. hr., M. epi-cerato- 
branchialis; M. rad., radiating muscle; No. 1, No. 2, branches of vagus. 
PLATE 35. 
Mu steins antareticus. 
Fig. 6. The anterior portion of the dorsal aorta with the efferent branchial, cephalic, 
&c., arteries; from the ventral aspect (nat. size). 
The efferent branchial arteries are brought into one plane by their ventral 
ends being reflected outwards. 
Fig. 7. The coeliaco-mesenteric artery ; from the ventral aspect (nat. size). 
Fig. 8. The brain and anterior part of the spinal cord, showing the arteries on the left 
side, the veins on the right; from the dorsal aspect (nat. size). 
Dien., diencephalon (=thalamencephalon) ; Epen., epencephalon or cere¬ 
bellum ; Mesen., mesencephalon (optic lobes) ; Meten., metencephalon or 
medulla oblongata ; Myel., myelon or spinal cord ; Prosen., prosencephalon; 
Bhinen., rhinencephalon or olfactory lobe. 
Fig. 9. Part of a longitudinal horizontal section of a frozen specimen, showing the con¬ 
nexion of the chief veins with the sinus venosus and precaval sinus ; seen 
from the dorsal aspect (nat. size). 
Lr., liver; p., partition dividing hepatic sinus into right and left com¬ 
partments ; Peric. perit. Sept., pericardio-peritoneal septum. 
Fig. 10. Diagrammatic view of the head with the chief blood-vessels ; from the left 
side (nat. size). 
Aud. eaps., auditory capsule; C. br. 5, dorsal end of fifth cerato 
branchial; C. hy., dorsal end of cerato-hyal; Ep. br. 5, ventral end of fifth 
epi-brancliial; Ply. Mn., ventral end of hyomandibular ; Mck., proximal end 
of lower jaw ; PI. Qu., proximal end of upper jaw ; Spir., spiracle. 
Fig. 11. The left orbital artery, showing the branches to the eye muscles (nat. size). 
5 A 
MDCCCLXXXVi. 
