ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 439 



humour, due to stronger fibrils and a denser inter-fibrillary substance. 

 In all the Amphibians and Chelonians investigated, the zonula consists 

 of two parts, the actual zonula-fibres and a delicate interstitial fibrillar 

 network. This fine network is in direct connexion with the zonula 

 fibres, and it shows differences in degree of development in different 

 forms. Its great interest is that it here forms a permanent character, 

 while in higher Vertebrates it is only a transient embryonic stage. The 

 vitreous humour everywhere shows the well-known fibrillar structure, 

 with anastomosis of the fibrils. A definite and constant structure is 

 always demonstrable. The fibrils show a tendency to invade, secondarily, 

 any structures that may be in the vitreous humour or surrounding it. 

 With the exception of Rana, all the forms investigated showed a marked 

 difference in the grouping of the fibres in the nasal and temporal 

 halves of the eye. In Salamandra two specially differentiated groups 

 of fibres are visible, and the fine fibrillar network shows a concentric 

 arrangement on the nasal side, which is less marked on the temporal 

 side. In Rana the tractus centralis is noteworthy, and the fibrillar net- 

 work is looser and less regular than in Salamandra. 



Details of the structure of the vitreous humour in Tropidonotus, 

 Coluber, Lacerta, and Testudo are also given. 



Nerve-endings in Pericardium of Man and other Mammals.* 

 W. Martynoff describes the numerous encapsuled nerve-endings (the 

 corpuscles of Golgi and Mazzoni), which lie in the fibrous and serous 

 layer of the pericardium of man. They were not found in other 

 mammals. In the pericardium of man and of other mammals there are 

 unencapsuled nerve-endings, which take three forms — unencapsuled 

 coils, dendriform terminal ramifications, and modifications of the 

 dendriform apparatus. As to nerve-endings in the single layer of flat 

 epithelium, Martynoff saw fine fibres given off from the sub-epithelial 

 plexus, which extended directly under the epithelial cells and gave off 

 on their course short filaments. These filaments ended in knob-like 

 thickenings apposed to the bases of the epithelial cells. 



Structure and Innervation of Dentin. f — C. Fritsch describes the 

 " funnel-fibres " (Trichterfasern) extending from the connective tissue 

 of the pulp to the lamina terminalis interna, arising from the plexus of 

 fibres ; the peripheral sheath of the dentin-tubules ; Romer's substance 

 outside each tubule ; in each tubule a massive process of the odontoblast 

 cell ; surrounding the process a lymph-space which can be injected ; and 

 in the lymph-space some of the nerves of the tooth. He has been able 

 to trace nerve-fibres into the substance of the dentin and into the 

 lymph-spaces. 



Grafting Pieces of Cornea.} — Bonnefon and Lacoste have ex- 

 perimented with the rabbit. When a fragment of living cornea is 

 implanted in a healthy cornea it is assimilated, whether autoplastic or 



* Arch. Mikr. Anat., lxxxiv. (1914) lte Abt., pp 430-37 (2 pis.). 

 t Arch. Mtt-r. Anat., lxxxiv. (1914) lte Abt., pp. 307-20 (2 pis.). 

 % Comptes Rendus, clviii. (1914) pp. 2017-19. 



