STUDIES IN THE RETINA. 447 



the membraua Hm. externa when the i-ods and cones are 

 broken away (cf. Hoffmann's figures [Broun's ' Thierreich ; 

 Amphibien/ pi. xxiii, 11 — 18, and pi. xxiv, 2 — 8] with 

 Max Schultze's ['Arch, inikr. Anat.,' Bd. v, pi. xxii]). The 

 latter author traced the threads of his " Faserkorb " proxi- 

 mally into the connective tissue of the outer nuclear layer, 

 but inasmuch as distally they ran on to the outer limbs of 

 the rods, he clearly wished to see in them the ends of the 

 nerves (cf. Strieker's ' Handbuch '). Hoffmann, who figures 

 the basal threads as running only a short way down the inner 

 limbs of the Amphibia, and then only loosely applied, appa- 

 rently regarded them as nothing more than hair- like prolon- 

 gations of the membrana lim. externa. Further, as stated, 

 Max Schultze described a continuation of his " Faserkorb " a 

 short way down the outer limbs. Hoffmann (loc. cit.) also 

 figUT^es somewhat similar threads running on to the outer 

 limbs of amphibian I'ods ; these he could not explain because 

 his basal threads Avere not supposed to run the whole length 

 of the inner limbs. 



There seems, then, to have been a distinct tendency to 

 attribute to the inner limbs in the Amphibia a system of 

 longitudinal fibres, though apparently not so pronounced or 

 complete as the " Faserkorb " of the inner limbs of the 

 human rods and cones. 



We may say, then, that the rods are thought to be longi- 

 tudinally striated, but while the inner limbs are externally 

 striated with fibrils the outer limbs are marked by furrows. 

 My own observations entirely confirm the existence of longi- 

 tudinal stride; but those on the inner limb and those on the 

 outer limb are not distinct in kind from one another, but are 

 parts of one system. 



Long before I had succeeded in discovering the true rela- 

 tions of these striations to one another, I had noticed that 

 the markings on the outer limbs consisted far more of longi- 

 tudinal rows of dots than of furrows. The rows, though 

 mostly continuous, are not always strictly parallel ; and the 

 dots only occasionally fall into circular series running nearly 



