90 



BRITISH PALAEOZOIC ASTEROZOA. 



Description. — Casts from tlie imprint show the apical surface with the ossicles 

 somewhat disturbed, and it is not easy to reconstruct the form. I believe, however, 

 Text-fig. 49 to be a reasonable reconstruction and to give a fair idea of the species. 



There are a few rounded disc-ossicles omitted in the drawing. The remainder 



Text-fig. 49. — Reconstruction of apical svirface of Mesopalcraster (?) UintuHirdtnsis (based 



on E. 13153). x 12. 



of the structure is obviously of a simple type. The noteworthy features are the 

 large proximal supero-marginalia, the large rounded primary radialia, and the short 

 broad obtuse arm. 



The specimen may be the young of an unknown species. 



Horizon and Localitij. — Lower Ludlow mudstones of Leintwardine, Hereford- 

 shire. 



4. Mesopalaeaster (?) sp. Plate IT, fig. 3 ; Text-fig. 50. 



Material. — Among the numerous specimens in the Royal Scottish Museum, 

 from the Scottish Silurian of Gutterford Burn, there is only one fragmentary 

 imprint which can be referred to any member of this group of families. It is 

 registered as 183. 



Text-fig. 50. — Plan of base of arm (apical surface) of Mesopaheasier (?) sp. (based on Roy. Scott. Mus., 



no. 183). X 12. 



Description. — The cast shows a very fragmentary view of the apical surface. 

 The inner portion of the disc is entirely free from ossicles, and possibly was covered 

 with a leathery skin which possessed few calcifications. The bases of the arms 

 may be seen extending from the disc. There is a distinct intermarginal area, and 

 in consequence the supero-marginalia are carried forwards well towards the centre 

 of the disc. As is usual in such cases, the most proximal supero-marginal is a little 

 smaller than the succeeding supero-marginalia. All these ossicles have the 

 characteristic bent-finger shape. Radialia and adradialia of the usual form may 

 also be recognised. 



