SCOMBRID^. 
471 
attaining a length of about 0’3, but usually smaller. Head slightly 
longer than deep ; inner pair of postero-superior fossae on cranium 
somewhat expanded in front, extending half the length of the 
cranium. Bones of opercular apparatus marked with irregular, 
radiating, rounded wrinkles or ridges. 
Form. ^ Log. Lower Eocene (London Clay) : London Basin. 
P. 623 a. Imperfect head with opercular apparatus, about 0*16 in 
length, marked by Egerton as intended to be the type 
specimen of this species; Sheppey. The irregular 
wrinkling on all the opercular bones is well shown. 
Egerton Coll. 
P. 1753. More imperfect similar head, partly decaying, labelled by 
Egerton ; Sheppey. Egerton Coll. 
35687. Equally small imperfect head, showing jaws; Sheppey. 
Purchased, 1859. 
28856. Large head,'showing jaws ; Sheppey. Purchased, 
38916. Cranium 0*095 in length, with foremost vertebral centrum 
fused with basioccipital; Sheppey. The parasphenoid is 
partly broken away, exposing a large basicranial canal. 
The vomer bears minute teeth arranged in a small, 
median, longitudinally-extended patch. Bowerhanh Coll. 
P. 1755, More imperfect larger cranium ; Sheppey. Egerton ColL 
P. 1693 a. Smaller cranium, showing minute teeth on edge of 
palatine bone; Sheppey. Egerton Coll. 
P. 1698b. Imperfect head, partly decaying, displaying mandible; 
Sheppey. Egerton Coll. 
39445. More imperfect decaying head ; Sheppey. Boiverhanlc Coll. 
P. 9481. Pyritised and partly decaying larger specimen ; Sheppey. 
EimisJcillen Coll. 
39231. Fine head 0*17 in length from hinder border of quadrate to 
tip of premaxilla; Sheppey. The premaxillae are less 
produced in front of the cranium than in Cyhium and 
Acanthocyhium. Bowerhanh Coll. 
P. 159. Imperfect large cranium ; Sheppey. Purchased, 1880. 
28624. Imperfect larger cranium ; Sheppey. Purchased, 1853. 
33305. More imperfect large cranium ; Sheppey. Purchased, 1858. 
