ON THE FOSSIL THYLLOPODA OF THE PALEOZOIC ROCKS. 345 



from the Lower Silurian of Girvan, Ayrshire, where Mrs. Gray has made 

 a large collection. 



The peculiar ' corded ' dorsal margin of the valves may have reference 

 to some longitudinal, narrow, intermediate ligament or plate, as in 

 Jihinocaris and Mesothyra. 



§ VII. 1895. A new species of Ceratiocaris (C. relicosn, J. it W.), 

 preserved in the Museum of the Geological Survey, was described in the 

 'Geological Magazine,' decade 4, 1895, vol. ii. pp. 539, 540, pi. xv., 

 figs. 1«, 16. It is from the Silurian beds of Ludlow, Shropshire, and is 

 allied to C. cassioides, from that locality. Traces of a peculiar reticulate 

 sculpture constitute its distinguishing feature. 



§ VIII. 1895. Lingulocaris.- — In the same number (378) of the 

 ' Geological Magazine,' 1895, at pp. 541, 542, a specimen of Lingulocaris 

 linguUtcomes, Salter, belonging to the Rev. G. C. H. Pollen, S.J., F.G.S., 

 was figured and described. It came from Capel Arthog, North Wales, 

 probably from the Ffestiniog or middle division of the Lingula-flags. 

 Hence we may add ' Lingidocaris ' to ' Ilymenocaris ' for that formation 

 at p. 425 of our Twelfth Report (fifth line from the bottom). 



§ IX. 1896. Devonian species of Ceratiocaris (?). — In the ' Monograph 

 of the Devonian Fauna of the South of England,' Palseont. Soc, vol. iii. 

 part 1, 1896, the Rev. G. F. Whidborne describes and figures three obscure 

 casts of Ceratiocaris, one, C. (?) subquadrata, sp. nov., p. 7, pi. i., fig. 5, 

 from East Anstey ; another, Ceratiocaris (?) sp., p. 8, pi. i., fig. 6, from 

 Sloly ; and the third, somewhat indistinct specimen, namely, Ceratio- 

 caris (?), sp., p. 8, pi. ii., fig. 12, from Croyde. 



§ X. 1896. Entomocaris and Ceratiocaris. — A collection of Ceratio- 

 caris-like Crustaceans from the Lower Helderberg Formation (Upper 

 Silurian), near Waubeka, Wisconsin, has afforded Mr. R. P. Whitfield, 

 of the American Natural-History Museum, New York, the opportunity 

 of determining two new species of Ceratiocaris, and a new genus {Ento- 

 mocaris), allied to Ceratiocaris, but differing from it by the carapace- valves 

 being ' strongly curved in front and behind on the dorsal margin,' and by 

 the posterior margin not being truncate, as in Ceratiocaris, but obtusely 

 rounded. Entomocaris Telleri, Whitfield (p. 300), is figured in pi. xii., 

 of full size, but slightly distorted by pressure. Including the four exposed 

 body-segments and the trifid appendage, it is about 21 centimetres 

 (about 8 inches) long; and the valves are about 13| centimetres long 

 by about 6^ high. Some indications of the swimming-feet attached to 

 the body are visible where one valve has been partially broken away from 

 the internal cast. Some mandibles, supposed to belong to this species, are 

 shown in pi. xiv., figs. 1, 2 ; and the caudal appendages in fig. 9. 



Ceratiocaris Monroei, Whitfield (p. 301, pi. xiii., figs. 1-5, and pi. xiv., 

 figs. 3-8), is carefully described from one nearly perfect and an imperfect 

 specimen, together with body-segments, caudal appendages, and some 

 mandibles. The carapace-valves seem to have been about 7^ centimetres 

 long and 4 high. 



Ceratiocaris podiiriformis, Whitfield (p. 302, pi. xiv., fig. 10), is 

 represented by a small specimen of abdominal segments and caudal spines. 



§ XI. 1896 Echinocaris Whidbornei, J. and W., noticed in our 

 Seventh Report (for 1889), p. 63, has been redescribed and refigured by 



