696 PROF. W. J. SOLLAS ON SILUEIAN [NoV. 1 899, 



rounded and thickened to form one side of a circular aperture for 

 the passage or insertion of the arm, and the other half of the aperture 

 is completed by the thickened margin of a similarly excavated 

 adjacent or adradial plate. The adradial plates form a pair, which 

 meet in the interradius. The arrangement is similar to that which 

 occurs in the genus Euthemon, to be next described ; in the latter, 

 however, the plates are not overlapping, but tesselated. The over- 

 lapping of the plates is less on the ventral than on the dorsal side, 

 a diiference which is probably due to the less amount of displace- 

 ment suffered by the ventral plates ; and this, again, is explicable on 

 the assumption that the ventral surface was flatter than the dorsal. 



The arms. — The arms of this species do not exhibit that 

 marked increase in size, as their position in the series becomes 

 more distal, which is characteristic of Eudadia Johnsoni. Their 

 average length is 25 mm. Near their tapering extremities the arms 

 present on both dorsal and ventral surface three plates, two of 

 which are lateral and one median, recalling the characteristic 

 plating of an Ophiuroid arm ; but nearer the origin the number 

 of conspicuous plates on either surface is increased to four or even 

 more, and smaller supplemental plates are inserted between them 

 in a manner precisely similar to that already described in the case 

 of Eudadia Johnsoni. The larger plates, swollen at first and 

 becoming mucronate finally, are produced into a short awn -like 

 termination. 



A search, which proved unsuccessful, was made for some trace of 

 vertebral ossicles : had these structures been present originally, 

 they must either have been very small or some traces would still be 

 discernible. In Lapivorthura, which occurs in the same rocks, the 

 vertebral ossicles are the most obvious elements in the brachial 

 skeleton. 



The distinction of Eudadia Woodivardi from E. Johyisoni rests 

 on the smaller number of arms possessed by the former and the 

 closer approach of these to equality in dimensions. The specimen 

 selected as the* type 'is exhibited in the Oxford University Museum, 

 and bears a label stating where its description may be found. 



Euthemon^ igeena, gen. et sp. nov. (Figs. 3 & 4, p. 698.) 



This dainty little star-fish bears the label ' Crinoid ?, Croft Farm,^ 

 Wenlock Limestone.' It retains its calcareous composition, and 

 lies embedded in limestone with the oral surface uppermost. The 

 portion preserved consists of the remains of a depressed spheroidal 

 or subpentagonal test, several pairs of arms, and the buccal 

 armature. 



The arms much resemble those of an Ophiuroid in outward 

 appearance, but proceed from the test in pairs, as in Eudadia : a 

 single arm on one side of a radius having its fellow symmetrically 

 placed on the other. There were at least two pairs of arms to each 

 radius, or twenty arms in all. Additional pairs may have been 



^ ev9r]fi(»v, well-made. 



^ Croft Farm is situated in the Malvern district. 



