Sheppard : Eryon aniiqnus Broderip, /rcwi the Lias. 9 



Lyme Regis,* is not well indicated on the Yorkshire example. 

 At a distance of 4.5 centimetres occurs a second indentation 

 called the cervical notch by Dr. Woodward, extending into the 

 carapace to the extent of 1.25 centimetres. The carapace in 

 front of this is coarsely tubercnlated, and its edge is serrated. 



In front of the carapace are the impressions of two anten- 

 nules ; the antennules themselves, to the length of nearly a 

 centimetre, (together with the greater portion of the right 

 claw, etc.), occur in the upper portion of the nodule, and clearly 

 indicate their segmented character. 



Unfortunately in the Yorkshire specimen, the smaller 

 thoracic legs are not shown. As in the Lyme Regis example, 

 described by Dr. Woodward, however, it possesses only one of 

 the first pair of chelate thoracic legs, the comparative length of 

 which is such a distinctive feature of E. antiquus. The total 

 length of the example preserved in the nodule now being 

 described, is 8.25 centimetres. The abdomen, so far as it is 

 exposed, measures 4.25 centimetres. Its widest part appears 

 to be at the first segment, which is slightly over 4 centimetres 

 across. The extremities of this are curved, are better exposed 

 than the other segments, and clearly shew the points of 

 attachment of the legs. Each segment, which is coarsel}^ 

 granular, bears a well-defined keel on the centre of its tergal 

 arch. In the nodule, to the left of the first segment, is a small 

 claw, evidently belonging to one of the smaller legs. 



As already explained, the tail-lobes or swimmerets are not 

 exposed. 



The surface of the carapace is strongly granulated. The 

 central or dorsal line is marked by a ridge or keel, in addition 

 to which two rounded ridges further sub-divide the carapace 

 longitudinally. 



Various species of Eyvon are recorded from the well-known 

 Solenhofen Limestone, and have been described by Spence- 

 Bate. f That writer draws attention to the rarity with which 

 the eyes are found in these fossil forms, and Dr. Woodward 

 also emphasises the point, though he refers to one or two 

 instances in which the eye occurs. In the specimen now being 

 described, however, the left eye is exceptionally well shown,. 



* On Eryon antiquus Broderip sp. from the Lower Lias, Lyme Regis, 

 Dorset. Geol. Mag., Oct. 1888, pp. 433-441. See also Q J.G.S., 1866, 

 pp. 494-502. 



t Geol. Mag., 1884, p. 307. 



1909 January i. 



