194 
OSTEOSTEACI. 
1854. Plectrodus ( Sclerodus ) pustuliferus, E. I. Murchison, Siluria, 
pi. xxxv. figs. 9-12. fry 9 dfF-F 3-7 ,i.QC>rv. 
1854. Plectrodus mirabilis, R. I. Murchison, ibid. pi. xxxv. figs. 3-8. 
1870. j Eukeraspis pustuliferus, E. R. Lank ester, Pishes Old Red 
Sandst. pt. i. (Pal. Soc.), p. 58, pi. xiii. figs. 9-14. 
Type. Portions of cornua. /*sf- (f c-erf. 
The type species, of small size, the maximum total length of the 
shield with its cornua being about 0-05. Cornua flattened from 
Eukeraspis pustulifera (Ag.).—Outline of shield, after Lankester. op., ant- 
orbital prominence; me., marginal cells; ip., interorbital prominence; 
pv., post orbital valley. A. Portion of ornament, much magnified. 
above downwards, twice as long as the body of the shield ; the ex¬ 
ternal denticulations stout, smooth, and irregularly spaced, with 
or without feeble intermediate points ; superficial tuberculations 
numerous, small, rounded, and closely arranged. 
Form. Sf Loc. Upper Ludlow and Downton Sandstone ; Hereford¬ 
shire. 
45949, a, b. Impression of cornu, and two imperfect shields, figured 
by Lankester, op. cit. pi. xiii. figs. 11, 13, 14; Downton 
Sandstone, Ludfoi;d Lane, Ludlow. Licjlitbody Bequest . 
45970, 45973. Cornu and two fragments; Ludford Lane. 
IAglitbody Bequest, 
