MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 1 55 



Fig. 6. Anophthalmia larva (presumably of A. tellkampfii) ; Emerton del.— 6a, antenna; 66, maxilla; 6c, labium and 



labial palpi ; 6d, labrum. > 



Fig. 7. Pupa, presumably of A. tellkampfii. Emerton del. 

 Fig. 8. Adelops Mrtua Tellkf. Emerton del. 



Fig. 9. Adelops hirtus Tellkf. Larva. Emerton del. — 9a, antenna. 

 FlG. 10. Balrisus 8pretii8. Emerton del. 

 FlG. 11. Quedius fulgidus. Emerton del. 



Figs. 12 and 13. Staphylinid beetles, not identified, from caves. Emerton del. 

 Fig. 14. An unknown eyeless Coleopterous larva from Bat Cave. Emerton del. 

 Fig. 1"). A staphylinid larva, not identified, from cave. Emerton del. 

 Fig. 16. Blastoderm cells on surface of egg of the cave spider, (Anthrolia mammouthia). Author del. 



Plate XXI. 



FlG. 1. Brain and eyes of an undetermined Cambarus with normal eyes; c, cornea; op. n, optic nerve; ant 1 , first an- 

 tennal nerve ; ant 2 , nerve of second pair of antennae. 



FlG. 2. Brain and rudimentary eyes of Orconectes pellucidus, lettering as in Fig. 1. 



Fig. 3. Section of eye of Orconectes hamulatus Cope and Packard; op. gang., optic ganglion ; g. c, ganglion cells ; hy., 

 hypodermis; mus., adductor muscle ; con. c, connective tissue cells. 



Fig. Ha. Section of the same, near the middle of the eye; op. n., optic nerve; a, a mass of ganglion-cells extending 

 to the end of the cornea. 



Fig. 36. Section very near the preceding; 3c, connective tissue cells from the side of the optic ganglion; 3d, ganglion 

 cells, with the walls nearly effaced ; x, a large one surrounded by those of ordinary size ; 3e, a few con- 

 nective tissue cells iu the place occupied by the rods and cones of the normal eye; 3/, hypodermis at end 

 of the eye, iu place of the cones of the normal eye, the cell walls mostly obsolete ; 3g, nuclei. 



FlG. 4. Auditory seta? from within the ear from an undetermined Cambarus, with normal eyes ; 4', one of the same 

 more highly magnified. 



FlG. 5. Seta) from 0. pellucidus from Indiana ; situated around the entrance to the ear; 5a, auditory setae from the 

 auditory sac of the same. 



Fig. 6. Auditory seta) from the ear of Orconectes hamulatus ; &a, the same enlarged. 

 All the figures drawn by the author. 



Plate XXII. 



Fig. 1. Chlmnius pensylvanicus. — Head dissected to show the brain, with optic ganglia (o. g.) and optic nerves and 



eyes; pc. I., procerebral lobes, or central part of the brain. 

 Fig. 2. Anophthalmus tellkampfii. Head, showing the central portion or brain proper, the optic ganglion and optic 



nerves with the eyes being totally abolished. 

 FlG. 3. Anophthalmus tellkampfii. Longitudinal or sagittal section of the head ; pel, supracesophageal ganglion ; s. m, 



subovsophageal ganglion ; /. g., frontal ganglion ; mx. »., nerve to the maxillae ;'mx. m., maxillary muscles ; 



mx', base of maxillae ; I. «., nerve to the lingua (I.) ; in., mouth; md., mandible ; Ibr., labrum ; com., com- 

 missure. 

 Fig. 3a. The same; longitudinal section on one side of the preceding; sg', sg 2 , salivary glands; I, lingua; pv, proven- 



triculus; at, stomach. 

 FlG. 4 to 4 e, horizontal sections through the brain of Anophthalmus tellkampfii; Af, vertical section. For the sections 



see PI. XXIII, fig. 2 to 2c. 

 FlG. 5. Orconectes pellucidus, from a cave in Indiana. Olfactory rods on the terminal three joints of the outer flagellum. 

 FlG. 6. Setae from near opening to the ears of 0. pellucidus, from cave in Iudiana. 



Fig. 7. Olfactory rods of Orconectes pellucidus ; 6a, 66, 6c, the same magnified, with nerve-cells in the base. 

 All the figures drawn by the author with the camera lucida. 



Plate XXIII. 



Fig. 1. Asellus communis. Op. g., optic ganglion; op. n., optic nerve; e., eye; rec, retinal cells; la, portion of the brain, 

 with the optic ganglion and optic nerve and eye of the same enlarged ; 16, section through th j headaudbraiu 

 of Cozcidotwa slygia, showing the entire absence of the optic ganglion and optic nerve, and the rudimentary 

 eye ; ret., rudimentary retina ; lc, sections through the rudimentary eye, composed of two facets; Id to Id", 

 sections through the eye of the same ; at Id a single facet; at Id" three ; at Id" a single lens surrounded 

 by the retina. 



Fig. 2 to 2c, vertical sections through the head and brain of Anophthalmus tellkampfii. 



J'n.. 3, '.'a. 36, 3c, '?.d, sections through the head and eyes of Adelops hirtus, showing the entire absence of optic ganglia 

 and optic nerves; at 3a' the eye is seen with rudiments of three lenses surrounded by the rudimentary pig- 

 ment. 

 All the figures drawn by the author with the camera. 



