AND MESOZOIC FISHES. 441 
quite thin 2iosteriorly. Its anterior extremity is excavated into an oval cujx The 
suiiposed mandible is flat, and in a horizontal iMaiie, but is more robust than tlie 
ceratohyal. If there were any orbital bones they have left no traces. 
Measurements. 
MM. 
Transverse diameter skull near posterior end of maxillary ; 200 
Length of parasjihenoid ; 30 
Width of parasphenoid at occipital cotylus ; 25 
Width of parasphenoid at middle; 20 
Diameters of anterior face of basihyal ; 1 1 1 
I transverse; 27 
Width of basibranchial ; 9 
Length of ? ceratohyal ; 39 
The specimen above described was found by Jacob Boll in the Permian forma- 
tion of Texas. 
ACTINOPTERYGIA. 
LEPIDOTIDJE. 
MACREPISTIUS Cope. 
Maceepistius aeesatus, geu. et. sp. nov. Plate XIX, Fig. 2, 
Cha. Gen. Dorsal fin elongate, consisting of niany rays ; caudal fin demi- 
heterocercal, with fulcra on the superior border ; anterior to this fin the fulcra are 
little different from ordinary scales. Scales rhombic. Teeth on jiremaxillaiy bones, 
vomer and palatines, all with obtusely rounded crowns on short jieduncles. except- 
ing those on the premaxillary and the opjiosing part of the dentaries. where 
they are a little more conic. Usual head bones present, including supraorbitals, 
suborbitals and preorbital. 
This genus appears to be referable to the Lepidotidce^ , as defined by Prof. 
Zittel,^ although the evidence will not be conclusive until the anal and the paired 
fins are known, It differs from Lepidotus in the elongate dorsal fin, and in tlie al> 
sence of “ meisselfbrniigen Zahnen ” on the jiremaxillary. I jjrojrose that it be 
called Macrepistms. I add some other characters which may be of more than 
generic significance. The maxillary bone is well ^M’oduced posteriorly, but the man- 
dible is jiroduced much farther. The ceratohyal is well developed, and tlie 
branchiostegal rays are osseous and robust. No gular nor intermandibular bones. 
Preojoercular and other facial bones, unarmed. A considerable fossa anterior to the 
position of the ethmoid, which is bounded by an osseous bar on each side ; but 
1 Palseoutologie, Palwozoologie, III, p, 207. 
^ lu the Aiiiericau Naturalist for 1880 (December) I proposed the names of DatJediidie, Lenidotidm, 
Macroeemiidw and Aspidorh.vnchidm, m place of the uauies Stylodoutidie, Si)haTodoiitidie, SfiupKlon- 
tid* and Ithynehodontidie of Zittel : names which are not taken from genera contained within them, and 
one of which (Saurodontida') Is preoccupied. 
