﻿276 ARTHRODIRA. 



Genus CONCHOPOMA, Kner. 

 [Sitzungsb. math.-naturw. CI. k. Akad. Wiss. vol. lvii. 1868, pt. i. 



p. 279.] 



Head relatively large and opercular apparatus robust, the oper- 

 culum convex and shaped like the valve of a bivalve shell ; dental 

 plates covered with irregularly arranged, stout, conical or rounded 

 tubercles. Trunk elongate and laterally compressed; median fin 

 continuous. Scales small, delicate, striated. 



Conchopoma gadiforme, Kner. 



1844. CcelacantJins munsteri, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. 



p. 173 (undefined). 

 1868. Conchopoma gadiforme, R. Kner, Sitzungsb. math.-naturw. CI. 



k. Akad. Wiss. vol. lvii. pt. i. p. 278, pis. i.-iv. 



Type. Well-preserved fishes ; Museums of Berlin and Strassburg. 



The type and only known species, of small size. Length of head 

 with opercular apparatus about equal to the maximum depth of the 

 trunk, and contained about four times in the total length. 



Form. <$f Loc. Lower Permian : Rhenish Prussia. 



P. 507, P. 3336. Nodule with nearly complete fish, wanting the 



* margins of the median fin and the paired fins, intended to 



be the type specimen of Coelacanthus muensteri, Ag. ; 



Lebach. Eyerton Sf Enniskillen Colls. 



Order II. ARTHRODIRA. 



Head with well-developed dermal or membrane bones ; principal 

 upper dentition on the elements of the pterygo-palatine arch. 

 Dermal armour of abdominal region consisting of large plates, of 

 which a dorso-lateral pair articulate by a movable ginglymoid joint 

 with the occipital border of the cranial shield. Notochord per- 

 sistent. Paired fins rudimentary or absent ; pelvic basipterygia [so 

 far as known] consisting of a pair of sigmoidal or club-shaped carti- 



Only a single family, that of Coccosteidae, can be referred to this 

 order with certainty ; but two other imperfectly known families 

 (Asterosteidae and Hylostomatidse) may also be placed here with 

 much probability of correctness. 



