38 H. M. BERNARD. 



cones originally ended in terminal vesicles, which, as above 

 stated, I feel sure must be the case. 



If the tips of the cones run as they do in the Anura, from 

 the first as far as the pigment cells, we should have here 

 essentially the same condition as we have above described for 

 the toads. One striking difference, however, has to be noted. 

 The basal vacuole in the adult Anura never swells to the 

 enormous size seen in the axolotl. It is true it may be very 

 much larger than is shown in fig. 7 (see e.g. fig. 6, d), but 

 only in immature eyes (fig. 13) does it somewhat resemble 

 those in fig. 8, c, g. 



Salamander. — As in the frog and the toad, the cones 

 here can be shown by heat fixation to reach to the pigment 

 layer (fig. 9, a — d). On reaching this layer, it is seen that 

 the pigment is raised as if round some terminal expan- 

 sion of the cone (see p. 27), Again, fig. 10 shows what I 

 take to be this expansion, although it may possibly be the 

 shaved-off tip of a rod. If my interpretation in this case is 

 correct, it is interesting because the specimen v^as fixed in 

 Perrenyi's fluid. And here I may add that though the com- 

 plete forms of the cones were first clearly seen in prepara- 

 tions fixed by heat — by which method they can always be 

 seen, — since knowing they are there I have recognised many 

 traces of them in sections prepared with other fixatives. 



The figures show the only transitional seines which I have 

 been able to find. I have not been quite so successful in 

 making satisfactory preparations of the retinas of either 

 salamanders or newts. This has been a disappointment which 

 I hope to overcome by renewed attempts. I may say, how- 

 ever, that what sections I have of adult salamanders, and of 

 Molge cristus and M. vulgaris, though not good enough 

 to show clearly and unmistakably the different stages side by 

 side, are yet quite suflficient to show that what one sees in the 

 eyes of the axolotl will, in all essentials, be found in these eyes 

 also. From the few figures given (6 — d, fig. 9) it will be seen 

 that the basal vacuoles are much smaller than in the axolotl, 

 and more nearly the size seen in the cones of the Anura. 



