Page:VCH Lancaster 1.djvu/82

A HISTORY OF LANCASHIRE comb-like structure of the palatal teeth. The first species, C. murchisoni, is common to the upper Coal Measures of Shropshire and Lancashire and to the middle Coal Measures of Staffordshire; while the second, C. cristatus, is widely distributed. Sagenodus inæqualis, which has an equally wide range, appears in Mr. Bolton's list, where the fish known as Hybodopsis wardi is likewise recorded as a Lancashire species.

The great group of fringe-finned enamel-scaled fishes, of which the African bichirs and reed-fish are the sole survivors, are represented in the county by an undetermined species of Rhizodopsis recorded by Mr. Wellburn from the Littleborough district, and also by scales from Pendleton and the Victoria pit which have been identified with R. sauroides. The large and well-known Megalichthys hibberti, of which the remains occur in all the British coal-fields, is common to the Lancashire area, as are also the species known as M. intermedius and M. pygmæus, which appear in Mr. Bolton's list. Teeth and scales of this genus are also recorded from St. Helens. Very widely spread is a species, Cœlacanthus elegans, of another genus of the same group, which is common to the Coal Measures of North America and Great Britain, and of which remains have been recorded from Lancashire. Bones and teeth of a second representative of the same genus from the St. Helens neighbourhood are identified with C. lepturus.

Of fish-spines or 'ichthyodorulites' of uncertain systematic position from the Coal Measures of the county, Mr. Bolton records the types respectively known as Gyracanthus formosus, Oracanthus milleri, and Lepracanthus colei. In the Geological Magazine for 1896 the same gentleman describes a fish-spine from the county which, under the name of L. spinatus, he identifies with the American generic type Listracanthus.

Leaving the fringe-finned group for that section of the enamel-scaled series in which the fins are of a more ordinary type of structure, we find the great Palæozoic family Palæoniscidae represented in the Coal Measures of the county by three species of the genus Elonichthys, namely E. aitkeni, E. semistriatus, and E. egertoni, all of which occur in the Littleborough district, while the genus is also recorded in Mr. Morton's list from the Victoria pit in the St. Helens neighbourhood. The first named species is typically a Lancashire fish. In addition to these we have from the Littleborough district another member of the family in question, Rhadinichthys monensis, a species typically from Anglesea belonging to a genus with numerous representatives. A scale of Rhadinichthys is also recorded by Mr. Morton from the Victoria pit; and Mr. Bolton includes in his list the two species known as R. wardi and R. planti, the latter being typically from the present county, while the former was described on the evidence of Staffordshire specimens.

Lastly, Acrolepis hopkinsi, which occurs at Littleborough, belongs to a large genus, and is common to the Carboniferous of Derbyshire, Yorkshire, Lanarkshire, and Belgium.

The remaining fishes recorded from the Coal Measures of the county are mostly referable to the family Platysomatidæ, the members of which are readily distinguishable from the Palæoniscidæ by the much deeper and more rhomboidal form of the body. Among these Chirodus granulosus, which is not included in the Littleborough list, is recorded elsewhere from Staffordshire and