﻿CONTENTS. V 



The Cuban Blind Fishes — continued p^ce 



Na.tuTt o{ the lia.bha.t of S/yg/io/a and Luct/u^a . . .188 



Abundance of SiygHola and Lucif'uga . . . . . 1^7 



Origin of the Culjan Blind Fishes ........... 197 



Physical environment of ^'/ty/tt'/a and Z,«c//«i'a and their Reactions to it .... 198 



Biological environment of .SV/^/co/rt and Z.«ci/«^a . . . . . . . .201 



General habits of Lucifuga and Stygkola .......... 204 



Breeding habits of Lucifuga and Stygkola .......... 204 



The Ovaries of Lucifuga and Stygkola .......... 206 



The Eyes of Lucifuga .............. 208 



The Eyes of Stygkola .............. 220 



On the Ovary and Ova in Lucifuga and Stygicola ......... 226 



Conclusions in Regard to Lucifuga and Stygicola ......... 232 



The causes of Individual and Phyletic Degeneration .......... 233 



LIST OF PLATES. 



FACING 

 PAGE 



Frontispiece. Entrance to Ariguanabo River, Cuba. Blind-fish rocks at base of Point Loma, San 



Diego, California Title 



Plate A. Twin and Shawnee Caves . 6 



1 . Chologaster papilliferus, Spelerpes maculkauda, Spelerpes stejnegeri, and Typhlotriton 



spelcEUS ............... 12 



2. Spelerpes longicauda and Typhlomolge ratlibiuii ........ 28 



3. Rhineura floridana ........!'.... 48 



4. Eye of Typhlops luntbricalis 54 



;. Amblyopsis 70 



6. Chologaster agassizii, Trogliclithys roscB, and Typhlichthys subterraneus ... 72 



7. Views of /^w^/vc/)j/j', early stages .......... 92 



8. Tactile organs of Amblyopsis and Chologaster . 98 



9. Heads of Zygonectes notatus, Chologaster agassizii, Chologaster papilliferus, Typhlichthys 



subterraneus, Troglichthys roses, and Amblyopsis spelceus . . . . .110 



10. VhoXo^ra^hs of the eyes of Amblyopsis and Troglichthys ...... 132 



11. Carboneria Beach near Matanzas. Cave of the Insurrectos, near the Carboneria . . 186 



12. Young of Z«c//7(i^(Z in Ashton Cave. Cave Isabella, showing roots .... 190 



13. Stygicola. (Preserved specimens) .......... 196 



14. Living Stygicolas ............. 200 



1 5 . Views of Lucifuga 200 



16. Sections of eye of Z,«i://>/i,'Vz ............ 20S 



17. Two sections through right eye of /.«[•//'«§» ........ 208 



18. Sections of eye of /,«iv/>c_^'W, showing contents of lens, capsule, and layers of retina . 20S 



19. Eyes of Lucifuga, showing pigment layer and retina and folding of sclera . . . 20S 



20. Eyes of Z.m7/>/;i,'a, showing differences in size and structure . ..... 216 



21. Sections through left and right eye-cavities of Z.//c//>(^a ...... 216 



22. Sections of eyes of Lucifuga, showing pigment layer and cells and oblique and rectus 



muscles . . . . . . . . . . . . . . .216 



23. Eye of old Z.?/tvy'«i,'<7, sliowinj; pigment mass and (ibrillar network aijout eye . . 216 



24. Eye of Lucifuga .............. 222 



25. E-ye of Stygicolas and Lucifugns ........... 222 



26. Eye of Stygicola .............. 222 



27. Ovaries of Lucifuga and Stygicola .......... 232 



28. Sections of ovaries ............. 232 



29. Sections of ovaries 232 



