LFPIDASTER GRAY!. 121 



covered with spines. The fact, however, that these pits extend over the articu- 

 lately surfaces of the adambulacralia shows that they are secondary and due to 

 weathering. Portions of the unweathered surfaces of a few of the adambulacralia, 

 e. g. those on arm xm figured, show raised pustules which carried stout spines 

 (Text-fig. 73). The ornament on the madreporite is well preserved and figured 

 (Text-fig. 74). 



Birmingham University Specimen (Plate VI, fig. 6; Text-figs. 75, 76). — This is 

 a small form which I believe to be an immature individual of the species. The 

 specimen is fairly well preserved, except that the right-hand portion of the disc 

 (as photographed) has been pushed over the left. In consequence it is difficult to 

 count the arms. These numbered at least eight, and possibly ten, but I am sure 

 there were not the normal thirteen arms present. This is not surprising if we 



75 



76 



"AdL 



Text-fig. 75. — Wash drawing of two arms of a young individual of Lepidas/er grayi. Ad., adradialia ; 



I.M., infero-marginalia. x 4. 



Text-fig. 76. —Plan of ossicles of a portion of the orai surface of a young individual of Lepidaster grayi. 



Ad., adambulacralia ; I.M., infero-marginalia; M. P., mouth-angle plates ; T.L., ventro lateralia. x 6. 



remember that in certain Recent species arms are added until far in adult life (see 

 Schuchert, 85, pp. 207 — 209). Only the oral surface is shown. The disc does not 

 appear to have so many ventro-hiteralia as in the previously described specimens. 

 The proximal adambulacralia also appear to have been but slightly, if at all, 

 modified. This latter is the only really distinctive character of the specimen which 

 might entitle it to rank as a distinct species. It might well, however, be merely a 

 sign of immaturity. 



Apical Surface. — Forbes states that " Mr. Gray has dissected from the slab the 

 extremity of one of the rays in such a manner as to permit an examination of both 

 upper and under surfaces of the same ray." This upper surface was figured and 

 described as " composed of numerous small polygonal nearly flat ossicula, closely 

 set, and of various sizes." Stiirtz copied this figure to try and establish the 

 relationships of Lepidaster with the Recent Scythaster. Schuchert remarks (p. 158) 

 that " Forbes's illustration leads the writer to believe that the abactinal plates 



