A contribution to the anatomy of the amphibian and reptilian retina / by J.W. Hulke.

  • Hulke, J. W. (John Whitaker), 1830-1895.
Date:
[between 1870 and 1879?]
Catalogue details

Licence: Public Domain Mark

Credit: A contribution to the anatomy of the amphibian and reptilian retina / by J.W. Hulke. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    17/30
    3 1 2, S ellcome ID b2245021x r. m X r 3 C: ^ 00 Oq V _ ^ ^ S § JCt No. TRACTS 1788(6) c 2 LAND TORTOISE^S RETINA. 17 Connective Frame. The membraua limitans externa, and interna resemble those of other reptiles, and do not require particular descrip- tion. The radial fibres arise from the membrana limitans interna by very expanded roots, and are stout and pillar-like in the ganglionic and inner half of the granular layer. They contribute largely to the tissue of this layer, and divide at acute angles near its outer surface into two or three branches which proceed to the layer of inner granules, where, rein- forced by other fibres taking their origin in the granular layer, they form areolae, Avhich lodge inner granules. A few fibres can be traced uninterruptedly from the point of division of the trunks in the granular layer to the inter- granule-layer, where they, togetlrer with other fibres derived from the framework of the layer of inner granules, are lost. Testudo Gr/ECa.— (Land Tortoise.) This retina closely resembles that of the turtle on a small scale. 1. Bacillary Layer. Rods and cones both occur. The large size of its body, and the small proportion of its shaft, give the rods a some- what cone-like appearance. They are best distinguished from the cones by the absence of the coloured bead, which characterises these. Both consist of a shaft imbedded in the choroid, and a body, the inner end of which rests in the membrana limitans externa, and is either rounded and in- cludes one of the outer granules, or is shuttle-shaped and prolonged inwards in the form of a pale band to meet a more remote outer granule. The rods are club-shaped. The shaft is a slender rectangle, of much higher refracting power than the thicker club-like body. The coues resemble the rods in shape, but contain a coloured bead, which lies in the outer h