266 



PROFESSOR MARSHALL AND EDWARD J. BLES. 



K.1 



K.4 



L 

 LN 

 LP 

 MO 



M P 



N 

 NO 

 N P 



O 



oc 



OD 



OF 



OS 



P 



PB 



Fig. 



Cartilage of first branchial 



arch 

 Cartilage of fourth branchial 



arch 

 Lung 



Lateral line 

 Lip 

 Somatopleuric layer of meso- 



blast 

 Splanchnopleuric layer of 



mesoblast 

 Notochord 

 Nephrostome 

 Head kidney 

 Olfactory pit 

 Opercular cavity 

 External aperture of opercular 



cavity 

 Opercular fold of hyoid arch 

 Optic stalk 

 Pharynx 



Q Intestine 



S Sucker 



S T Stomatodaeum 



T Thymus 



V C Posterior vena cava 



V D Ductus Cuvieri, or Cuvierian 



vein 



V H Hepatic vein 



V J Inferior jugular vein 



V K Venous sinus above sucker 



V M Mandibular vein 



V P Pulmonary vein 



V R Anterior cardinal vein 



V S Posterior cardinal vein 



V Y Hyoidean vein 

 W Liver 



Y Lymph space 



Z Septum between stomatodseum 

 and pharynx 



VIM Auditory nerve 



X Pneumogastric nerve 



Pituitary body 



1. 3^ mm. tadpole. Transverse section through the ear, 

 showing the development of the pericardial cavity and 

 of the endothelial lining of the heart : ( x 45). 



Fig. 2. 3| mm. tadpole. Median sagittal section of the anterior 

 half of the tadpole, showing the relations of the heart 

 to the pharynx and liver : (x 45). 



Fig. 3. 4 mm. tadpole. Transverse section through the middle of 

 the heart, showing the development of the heart and 

 pericardial cavity : (x 45). 



Fig. 4. 4| mm. tadpole. A diagrammatic figure of the anterior part 

 of the tadpole, seen from the right side, showing the 

 condition of the heart and blood vessels : (x 45). 



Fig. 5. 4| mm. tadpole. A diagrammatic transverse section through 

 the head, passing through the auditory vesicles, and seen 

 from behind. The figure shows an abnormal condition, 

 seen only in a single specimen of Bana tenvporaria, but 

 apparently constant in Bana esculenta, in which the 

 efferent vessel of the first branchial arch, which is shown 

 on the left side of the figure, forms a direct communica- 



