170 
ACTIX OPTEBYGTI. 
non-denticulated; but in the type and only known specimen none 
of the scales of the flank are exposed from the outer aspect, their 
hinder border being thus obscured. 
Form. Log. Purbeck Peds : (?) Dorsetshire. 
P. 7433. Type specimen ; probably from the neighbourhood of 
Swanage. Old Collection. 
Ophiopsis breviceps, Egerton. 
1852. Ophiopsis breviceps, Sir P. Egerton, Figs. & Descript. Brit. 
Organic Remains (Mem. Geol. Suit.), dec. vi. no. 6, pi. vi. 
Type. Nearly complete fish; Museum of Practical Geology. 
A robust species of small size, attaining a length of about 0*12. 
Head with opercular apparatus occupying slightly less than one- 
quarter of the total length ; maximum depth of trunk twice as 
great as the width of the caudal pedicle and contained nearly four- 
and-a-half times in the total length. Head and opercular bones 
coarsely ornamented with tubercles and rugae; teeth elongate- 
conical. Dorsal fin comprising not less than 35 rays and occupying 
the greater part of the hinder two-thirds of the trunk, not so deep 
as the trunk at its point of origin ; pelvic fins arising almost at the 
middle point between the pectorals and the caudal. Scales smooth 
and somewhat concave externally, with a coarsely serrated hinder 
border. 
Form. Sf Log. Purbeck Beds : Wiltshire. 
P. 3608. A typical specimen with scattered squamation and head- 
bones, and the fins only shown in impression; Wockley. 
near Tisbury. The premaxillae exhibit an upwardly- 
ascending extension, and the outer aspect of an operculum 
shows the coarsely rugose character of the surface-orna¬ 
ment. The vertebrae, as usual, are very delicate. 
FnnisJcillen Coll. 
46410. Imperfect hinder two-thirds of the trunk, with remains of 
dorsal fin ; near Tisbury. Cunnington Coll . 
P. 583. Fragmentary specimen labelled by Egerton as the counter¬ 
part of the original of his fig. 2, loc. cit.; Wockley, near 
Tisbury. Egerton Coll. 
P. 1094. Two specimens exhibiting vertebrae, scales, and other 
fragments ; Wockley. Egerton Coll. 
