Dr. H. Woodward—On the genus Eryon. 437 
In Oppel’s “ Palzontologische Mittheilungen” (1862) he figures 
several Hryon from Solenhofen; e.g. £. ‘arctiformis, Schlot. sp. 
(op. ae Tab. 3, He 1), and he marks (0, 0) “ Augenstiele,” and on 
Mabe 2, figs. 15 2; Me (0, 0) “ Hinschnitte im Cephalothorax fiir die 
eee In the description of the figure given by him (“Challenger” 
Report, p. xv) of Hryon calvadosii (after M. Moriére) ‘the orbits,” 
says Spence-Bate, “for the reception of the organs of vision are 
well preserved.” Bearing in mind the usually delicate nature of 
these organs, it is not surprising to find them more often represented 
by their orbital vacuities than by the eyes themselves.! 
We cannot follow Mr. Spence-Bate in his conclusions that we find 
‘in the same geological epoch some specimens of Zryon that are 
blind, and others with large and probably well-developed organs of 
vision” (op. cié. p. xvi). Such a deduction, based upon our present 
imperfect knowledge of fossil forms, would be as erroneous as to 
conclude that the Venus of Milo was originally sculptured without 
arms because they are now reduced to stumps. 
During the cruise of the “Challenger,” two genera of deep-sea 
Crustaceans allied to Hryon were obtained by Dr. v. Willemoes- 
Suhm, the late talented Naturalist to the Expedition, whose lamented 
death occurred before the completion of the voyage. 
By the kindness of Dr. John Murray, F.R.S.E., the Director of the 
“Challenger” publications, I am permitted to reproduce figures of 
these very remarkable living representatives of this well-marked 
and ancient family of Jurassic Crustaceans. 
The first of these, Polycheles cructfera, was dredged off Sombra 
Island, West Indies, in a depth of 480 fathoms ‘(op. cit. p. 127). 
Another specimen is mentioned (at p. 100) as having been dredged 
in the middle of the North Atlantic at a depth of 1900 fathoms, or 
rather more than two miles from the surface! (see Woodcut, Fig. 1). 
“The eye is lodged in a narrow cleft of the dorsal surface of the 
carapace, and projects beneath the antero-lateral angle of the cara- 
pace in the form of an obtuse point” (op. cit. p. 127). “ The animal,” 
says Mr. Spence-Bate, ‘“‘can have had only a very limited range of 
vision outwardly, by the aid of one lens above, and another below 
and a little in advance, and even this, from the apparent density of 
the cornea, must have been of a very imperfect character” (op. cit. 
p. 128). 
Another species, Polycheles Helleri, Bate, dredged to the north of 
New Zealand, in a depth of 520 fathoms, and again north of New 
Guinea, at a depth of 1070 fathoms, appears to have had equally — 
imperfect vision (op. cit. p. 139). 
The second form, Pentacheles euthrix (Woodcut, Fig. 2),was dredged 
off the Kermadec Islands in depths of 520 and 680 fathoms; and 
again off Matuku, in 315 fathoms. 
“The ophthalmopod is lodged in a notch in the carapace that is 
1 In the recent forms described by Mr. Spence-Bate the eye was found to be 
almost entirely concealed beneath the antero-lateral angle of the carapace, see wood- 
cut of ophthalmopod of Pentacheles gracilis (‘« Challenger” Report, or CrusTacea- 
Macroura, vol, xxiv. p. 114, fig. 28; also vol. xxiv. “plate xvii. figs, Ca, Cii.a, 
C iii. a.) 
