0STE0LEMD2E. 
385 
scales and head-bones apparently thinner than in the last-named 
species. 
Though regarded by Young as the type of a distinct genus, 
llhomboptychius , on account of the characters of the scales and 
teeth, the specimens mentioned below prove that no sufficient basis 
for the generic separation of this species from Megalichthys can yet 
be established. 
Form. fyLoc. Coal-Measures: South Scotland and North Stafford¬ 
shire. 
37320-21. Two slabs of shale exhibiting various bones and scales; 
Airdrie, Lanarkshire. The first specimen, which is to be 
regarded as the type, shows the left mandibular ramus 
and other portions of the jaws with teeth, the oral aspect 
of some of these bones being covered with numerous 
small, closely-arranged dental tubercles, as described by 
Young; the greater portion of the operculum is seen 
from the inner aspect, and several scales are preserved, 
showing not only fragments of the superficial ganoine- 
layer, but also, in some instances, a well-marked median 
rib on the inner side; a few of the characteristic slender 
ring-vertebrae also occur. The second specimen shows 
the pair of jugular plates and portions of jaws, with 
teeth, from the inner aspect; the larger teeth are trans¬ 
versely banded, and the external aspect of the bones is 
covered with ganoine. Purchased, 1863. 
P. 3324. Jugular plate; Gubbin Ironstone Shale, Shelton, North 
Staffordshire. Enniskillen Coll. 
37974-75. Two slabs with miscellaneous remains; Airdrie. 
Purchased , 1863. 
P. 3303. Group of head-bones; Carluke. Enniskillen Coll. 
P. 4465. Small slab with miscellaneous remains; Carluke. 
Enniskillen Coll. 
P. 4802. Greater portion of right maxilla with teeth; Palace Craig 
Ironstone, Airdrie. Armstrong Coll., transferred from 
Mus. Science f Art, Edinburgh, 1884. 
39248. Portion of maxilla ; Airdrie. Purchased, 1865. 
37973, 38010. Portions of two large mandibular rami showing the 
bases of teeth, one associated with detached scales; 
Airdrie. Purchased , 1863-64. 
PAET II. 2 C 
