OSTEOSMSSID®. 
79 
excessively long and narrow. There are remains of a 
short and broad ethmoid in front of the frontals (Jr.) not 
shown in the figure. The extent of the premaxilla, (jnnx.) 
is indicated on both sides, and it seems to have borne 
10 teeth. The best preserved tooth, at the hinder end 
of the left premaxilla, is shown of the natural size in 
fig. 2 b. The two postorbital cheek-plates aro exhibited, 
the lower (s.o.2) much the largest as usual. The charac- 
teristic fine tubercular ornament is observed on the 
operculum (op.) and also slightly on the upper cheek-plate 
of the left side. Fourteen branchiostegal rays are 
preserved on the right. There are also some rays of the 
right pectoral fin (pet.), the foremost being comparatively 
stout. Purchased, 1880. 
P- 638. A pyritised decaying specimen, labelled by Agassiz as 
intended to be the basis of his description of the species. 
It exhibits the large robust prefrontal bone on the right 
side. The maxilla is also well shown, with its charac- 
teristic dentition and a comparatively delicate small 
expansion behind. The preoperculum is evidently 
expanded at the angle, and there are remains of about 
14 pairs of slender branchiostegal rays. Egerton Coll. 
39448. Another decaying specimen comprising the opercular and 
branchiostegal apparatus, with the postorbital plates. 
The well-ossified upper end of each hyomandibular 
projects from the indurated clay. The left operculum is 
shown to be somewhat more than half as broad as deep ; 
while both this and the left lower postorbital plate 
exhibit remains of tho superficial ornament of radiating 
tuberculated lines. The number of branchiostegal rays 
appears to be slightly greater than in the last specimen, 
but they are very imperfectly preserved. Bowerbanh Coll. 
43020. Block of indurated clay with scattered remains, comprising 
the right mandibular ramus (PI. I. fig. 3), part of that 
of the left side, the right clavicle, scales, and other 
fragments. The dentary bone ( d .) bears traces of about 
21 teeth, and ascends behind into tho front part of the 
coronoid elevation. The outer face of the clavicle is 
considerably expanded throughout its length, though 
widest in its lower portion. Purchased, 1871. 
