352 
SELACIUJ. 
49474. Head and brancliial region, shown, of two thirds the natural 
size, in 1‘1. XVII. fig. 2, extending somewhat further back- 
wards and displaying the imperfect pectoral fins. The 
intertrabccular rostral cartilage is prominent ; a few cha- 
racteristic teeth are seen ; and there are distinct remains 
of some of the branchial arches and gill-clefts. 
Purchased, 1878. 
49475. Imperfect head, with the snout nearly complete, and crushed 
remains of the anterior portion of the trunk, with the left 
pectoral fin. A few teeth are exhibited, including one of 
the hindmost, shown, of four times the natural size, in 
PI. XVII. fig. 7. Purchased, 1878. 
49551. A less perfect specimen, exhibiting several teeth. The 
lateral aspect of the crown of an anterior tooth is shown, 
of three times the natural size, in PI. XVII. fig. 3. The 
posterior face of the crown in the lateral teeth appears to 
bo smooth. Purchased, 1878. 
P. 4020. A nearly complete trunk, imperfect in the anterior dorsal 
region, shown, of two thirds the natural size, in PI. XVII. 
fig. 1. The body is covered with a fine dense shagreen, 
and this, in addition to the fossilization of the muscular 
tissues, renders the outline distinct ; the fins, however, 
seem to have been destitute of shagreen towards all the 
free margins, except the anterior one, and their exact 
proportions are thus not detcnninable. Most of the ver- 
tebral centra are much broken, but their astcrospondylic 
character is evident, and in the abdominal region they are 
deeper than long ; in the caudal region their size very 
gradually diminishes towards the posterior extremity, and 
above the inferior lobe of the caudal fin the haemal arches 
are distinct. The small second dorsal flu {tP.) is completely 
opposed to the anterior half of the much elongated anal 
{an.). The pelvic fins {plv.) are large, atid arise about 
halfway between the pectorals {pet.) and the anal ; and 
at the base of each of these fins a numerous scries of 
delicate cartilages is distinguishable. The long caudal fin 
(c.) is well preserved, and shows very distinctly the single 
inferior notch near its hinder extremity. 
Purchased, 1883. 
48100-03. Pour imperfect examples of the trunk. Purchased, 1877. 
