164 MR. NEWPORT ON THE OCELLI 



Further I may mention, with regard to the question concerning the eye-spots in the 

 Arachnida, that I have found by dissection in the Scorpionidce, not only that these are 

 always situated in the exact place of eyes in other species, but also that they always 

 receive a nervous filament from the same optic nerve which supplies the distinctly recog- 

 nised organs of vision. 



These facts, I trust, will be sufficient to show the general correctness of the description 

 which I originally gave of the male Anthophorabia, that it is distinguished by the pos- 

 session of ocelli, both at the sides of the head and on the vertex. 



May 9, 1853. — To the foregoing remarks I may add a word on the condition of the eyes 

 in the so-called blind Crustaceans from the caves of Kentucky. Distinct eyes exist both 

 in Triura cavernicola and in Astacus pellucidus, Tellk. In Trmra the eyes have very 

 short pedicles, and are almost close together. In Astacus (fig. 11) they are partially 

 concealed beneath the front of the head (b) ; their pedicles are conical, much shorter than 

 in other species of the genus, and possess but little power of motion. The eye itself 

 (fig. 12 and 13 b), although existing as a distinct structure, is destitute of a pigmentary 

 choroid, in which respect it may be compared to the eye of the Albino. But the hardened 

 tegument which clothes the entire organ is thinnest and most transparent in that part 

 which forms the cornea (b) in other crustaceans ; so that, although the eye may be un- 

 fitted for distinguishing form, the creature may yet possess the faculty of perceiving the 

 small amount of actinic rays of light which penetrate into its subterranean abode. The 

 cornea also exhibits an appearance of being divided into a few imperfect corneales at the 

 apex of the organ (fig. 14), and the structure behind these into chambers, to which a small 

 but distinct optic nerve is given (fig. 13 d d). 



Probably other Articulata, which have been supposed to be entirely destitute of eyes, 

 and, consequently, of the power of perceiving light, will be found to have the tegument 

 which covers the place of the supposed lost organ thinner and more permeable to light 

 there than in other parts. It seems fair to infer that this may prove to be the fact in all, 

 from the already acknowledged susceptibility of some of the supposed eyeless insects to 

 the presence of light ; and also from the circumstance that in one of the Coleoptera, and 



in an Orthopterous insect, of the dark caves, Adelops hirtus and Phalangopsis ?, the 



eye, as in others of the tribe, is distinctly indicated, as already shown by Tellkampf and 

 by Thomson*. Hence we may fairly assume that the supposed eyeless Articulata differ 

 from others of their class rather in the degree, than in the entire absence, of power of 

 appreciating light. 



* Annals and Magazine of Natural History, vol. xiii. p. 112, No. 82. Feb. 1844. 





