168 
JTETEROSTRACI. 
JPteraspis croucTii. They are described under the name of Scaphaspis 
rectus, Lankester -*■, and are relatively longer and narrower than the 
shields named S. Uoydi , with more nearly parallel sides. 
Tig. 16. 
Pta cispis crouchi, Lank—Portion of shield, dorsal aspect, showing sensory 
canals. [No. 42163.] From Proc. Zool. Soc. 1887. 
37389. Imperfect specimen associated with a fragment of the shield 
of Phlyctcenaspis; Heightington. Purchased, 1863. 
*> v + 
42149-50. Tour imperfect specimens ; Heightington. Baugh Coll . 
38034 a. Internal cast of shield, figured by Lankester, op. cit. pi. ii. 
fig. 7; Worcestershire. Purchased, 1864. 
P.4107-8. Two specimens; Asylum Quarry, Abergavenny. 
Presented by Dr. D. M. McCullough, 1883. 
P. 4109. Internal cast of small shield ; from boulder in railway¬ 
cutting, Mainpliff, Abergavenny. 
Presented by Dr. D. M. McCullough, 1883. 
The following species of Pteraspis have also been described, but 
there are no examples in the Collection :— 
Pteraspis angustata, A. von Alth, Abhandl. k. k. geol. Eeichsanst. 
vol. vii. pt. i. (1874), p. 45, pi. i. fig. 11, pi. hi. figs. Q, 7._ 
Lower Devonian ; Iwanie and Ixriszczatek, Galicia. [Im¬ 
perfect shields.] 
Pteraspis mitchelli, J. Powrie, Geologist, vol. vii. (1864), p. 172 ; 
E. E. Lankester, Tishes Old Eed Sandst. pt. i. (Pal. Soc. 
1 Fishes Old Red Sandst. pt. i. (Pal. Soc. 1868), p. 23, pi. ii. figs. 5-8, 12, e* 
13, pi. vii, fig. 2. 
/*• s? 
