440 Dr. H. Woodward—On the genus Eryon. 
much broader at the anterior margin, and narrower posteriorly ; it 
carries a small, pointed cusp on the anterior surface, and passes 
outwards beneath the projecting angle of the carapace, and terminates 
in two small nodules, one on the outer, and the other on the lower 
side” (op. cit. p. 151). 
Three other species are recorded by Mr. Spence-Bate, viz.— 
P. obscura, north of New Guinea, depth 1070 fathoms ; P. levis, 
between Samboagan and New Guinea, 500 fathoms; P. gracilis, off 
Kandavu Island, in 610 fathoms. 
It can hardly be doubted that in these remarkable deep-sea forms 
we have the last survivors of a once numerous family of Crustacea- 
Macrura with broad and flattened carapaces, destitute of any rostrum, 
serrated more or less along their lateral margins, and generally 
marked by a strong cervical furrow which is usually branched 
laterally. 
That these modern forms should either be quite blind, or have 
but imperfect vision, does not seem extraordinary when we con- 
sider the very great depth at which they have been found living ; 
but it is quite certain that the fossil forms, both of the Oolite and 
Lias, inhabited comparatively shallow near-shore waters, as is proved 
by the nature of the deposits in which they occur, and the numerous 
terrestrial and shallow-water organisms found embedded with them. 
The absence of vision in the fossil forms cannot therefore be 
proved by comparing them with the recent ones, whose conditions 
and surroundings are so different. The species of Hryon from the 
Lias, having all, apparently, a dieresis in the outer lobe of the 
caudal fan, are evidently an older or less specialized form than those 
of the newer Solenhofen Stone (Upper Oolite), in which the dieresis 
is absent, the outer lobe of the caudal fan being in one piece; and 
this is the case also in the surviving deep-sea species. 
In a footnote to the “Challenger” Report on Crustacea-Macrura, 
Mr. Spence-Bate writes at p. 120 :—“ In the Quart. Journ. Geol. Soc. 
(1866) vol. xxv. fig. 1, Dr. Woodward delineated by the help 
of the fine examples in the cabinet of the Rev. P. B. Brodie, F.G.S., 
and those in the British Museum, a completely restored figure of 
Eryon barrovensis, M‘Coy, in which the scaphocerite is fixed at the 
extremity of a peduncle that is independent of that of the antenne. 
This condition not being in accordance with the anatomical structure 
of the Macrurous Decapoda, I am induced to think that the small 
pedicular plate at the extremity of the third pair of maxil * is in- 
tended, of which a drawing is given, fig. 31, p. 135, in this Report, 
and which in some recent species extends beyond the frontal margin.” 
In my figure referred to, the artist has correctly represented the pro- 
jecting latero-anterior angles of the frontal margin of the carapace of 
LE. Barrovensis as partially concealing the broad basal joint of the 
antenna, giving to it the appearance as if the antennal scale (scapho- 
cerite) was articulated to a distinct base, separate from the antenna. 
As such a structure is unknown, it is extraordinary that this should 
have misled so old and experienced a Carcinologist as Mr. Spence- 
Bate, and that he should not have turned to the text, where (p. 496, 
