80 ARTHUR DENDY. 



6. DESCRIPTION OF PLATES 1—10. 



Illustrating Mr. Arthur Dendy's paper on " Outlines of the 

 Developnaent of the Tuatara, Sphenodon (Hatteria) 

 punctatus." 



List of Reference Letters. 



Al. C. Alimentary canal. All. Allautois. Am. Amnion. Am. C. Amniotic 

 cavity. Am.O. Amniotic opening. Am.S. Slit along which amnion is not 

 yet closed. A.O. Area opaca. A. P. Area pellucida. Au. Auditory pit 

 (and vesicle). B.Ar. Bulbus arteriosus. B.I. Blood island. B.P. Blasto- 

 pore. B. V. Blood-vessel. Cb. Cerebellum. C. H. Cerebral hemispheres. 

 D. A. Dorsal aorta. Bib. Elbow. Ep. Epiblast. Bp. T. Epithelioid tubule 

 in heart. Bi/e. Ordinary paired eye. F.B. Fore-brain. F.L. Fore-limb. 

 F. Sp. Fold where the hypoblast turns round to run forwards, marking the 

 posterior limit of the anterior enclosure of the alimentary canal. G. fF. Ger- 

 minal wall. H. B. Hind brain. H. C. Head cavity. H. C. C. Connection 

 between the two anterior head cavities. H. C. M. Branch of head cavity in 

 mandibular arch. Z^. F. Head-fold. if. Z. Hind limb. H. M. md H. M.C. 

 Hyomandibular cleft.' Hi. Heart. Ef/p. Hypoblast. I. C. M. Intermediate 

 cell mass. Inf. Infundibulum. L. A. S. Line along which amnion and serous 

 envelope are united. Le. Lens of paired eye. L. F. B. Left half of roof of 

 fore-brain overlapping right half. Liv. Liver. L. Ju. Line of junction of the 

 two uprising amniotic folds above the medullary groove. L. L. Lower-layer 

 cells of blastoderm. L. L. M. Mesoblast derived directly from lower-layer 

 cells of blastoderm. L.L.T. Lower-layer cells with yolk. L.U. Line along 

 which the two halves of the roof of the fore-brain have united. Z. IF. Lateral 

 wing or sheet of mesoblast growing out from the primitive streak. Mand. 

 Mandibular arch. M. B. Mid-brain. M. C. Medullary canal. Mes. Meso- 

 blast. Mes.E. Epithelioid mesoblast on under surface of serous envelope. 

 M. 0. Medullary groove. Mo. Mouth. M. P. Medullary plate. M. S. 

 Mesoblastic somite. Na. Nasal pit. N. En. Neurenteric canal. Not. Noto- 

 chord. 0. Al. Ventral opening of unenclosed part of alimentary canal. 0. L. 

 Optic lobe. O.P.A. Opening into posterior enclosed part of alimentary 

 canal. Op. C. Optic cup of paired eye. Op. S. Optic stalk of paired eye. 

 O.V. Optic vesicle of paired eye. P.A.C. Posterior amniotic canal. Pa.E. 

 Parietal eye. P. Ao. Primitive aorta. P. C Pericardium (or coelomic space 

 which will give rise to pericardium). P. G. Primitive groove. Ph. Pharynx. 

 Pit. Pituitary body. P. P. S. Pleuro-peritoneal space. Pro. Am. Pro- 

 amnion, P/'. ^y. Primitive streak. P.S.M. Mesoblast derived from primitive 

 streak. P. V. Primary parietal vesicle. li. C. Radial corrugations in the 



