Dr. H. Woodward—On the genus Eryon. 435 
Another example of Eryon ( Coleia) antiquus from the same locality 
and formation having been obtained for the British Museum, it 
seems to me to deserve to be recorded and figured (see Plate XII.), 
as this is evidently a rather rare species in our Lias. 
Description.—The whole Bppcimen measures 114 centimétres in 
length; the cephalothorax is 54 centim. long and 5 &. at its broadest 
part just behind the cervical. furrow, and 4c. wide at its posterior 
border. The hinder border is nearly straight, being but slightly 
arched, or concave, forwards. Ata distance of 3c. from the pos- 
terior border there is a well-developed rather incurved tooth or 
spine marking the posterior margin of the first lateral indentation 
of the carapace 5mm. deep. At 3% centimétres from the posterior 
border the 2nd lateral roundly-incurved tooth arises. Here the 
carapace becomes narrower, being only 44c. in breadth. This 2nd 
rounded serration also marks the second lateral indentation 6mm. 
deep; this may be called the cervical notch, as it unites with the 
cervical furrow, which here crosses the carapace in a clearly-marked 
obtusely V-shaped line. In front of this cervical notch, the carapace 
again expands, forming a rounded lobe on each side, ending in a third 
antero-lateral tooth; here the carapace has contracted to a breadth 
of 24 centimétres; this tooth forms the outer border of the orbital 
fossa 6 mm. broad; the inner margin of which is formed by a spine 
6 mm. long, which rises up on either side of the deep frontal fossa, 
12 mm. across, and broadly U-shaped, which occupies in the cara- 
pace of Hryon that space usually filled by the rostrum in other 
Macroura, but which is not developed in the Eryonide. 
In this frontal fossa the antennules are seen with their three basal 
joints and their bifid flagella, the outer flagellum being 11 mm. 
long and the inner 16mm. _ Just inside the antennules are preserved 
the four distal joints of the two palpi (or endopodites) of the 3rd 
or external pair of maxillipedes. Only portions of the flagella of 
the outer antenna with their basal joints are preserved. Near the 
base of these, the flattened remains of the ophthalmopods are seen 
lying in the orbital fossa on each side. 
The great length of the first pair of chelate thoracic legs is very 
characteristic of H. antiquus, and strikingly in contrast with all the 
other species of Hryon, save H. bilobatus, E. longipes, and EH. Reden- 
bacheri, from Polenhofen (see Oppel’s Pal. Mittheil. pp. 16-18, 
tab. 3, figs. 2, 3,6). They are, in our fossil, 114 centimétres long. 
The 2nd pair, also chelate, are much smaller, being 44 c. long. The 
ord and 4th pairs were also chelate and the Sth pair simple. 
The abdomen measures 64 centimetres in length, including the 
telson, which is 2 c. long. Its widest part is at the 2nd segment, 
which is 384c. wide, the 6th being 24c.: the breadth of the 
swimmerets of the tail is 6Lc. The ‘telson is 14 mm. broad. The 
sternal arches of the segments are narrow near the centre, with wide 
intersternal membranes : ; but they become broader near their rounded 
epimeral borders. 
Hach somite or segment bears upon the centre of its tergal arch a 
strong tubercle; the whole surface of the segments being coarsely 
