Dr.R. H. Traqiiair — On Cycloptychius carhonarms. 243 



back. It is compressed laterally, and below the middle it is slightly 

 bent forwards again at a low angle ; m sitA the upper part is very- 

 oblique, the lower nearly perpendicular. There is no trace of a 

 symplectic, and, as in the recent Polypterus, it was probably absent. 

 The palatoquadrate apparatus also in form reminds us of that in 

 Polypterus, and forms a bony lamina extending from the front of the 

 lower part of the hyomandibular to the ethmoidal region ; its indi- 

 vidual ossifications cannot unfortunately be distinguished. The 

 orbit is placed far forwards, and surrounded by a chain of ossicles, 

 whose exact number can scarcely be determined ; as in Palceonisctis, 

 there is a very prominent one seen forming the inferior and the 

 greater part of the posterior orbital margin. The superior maxillary 

 bone (Fig. 3 mx.) is stout and broad, till it comes to the orbit, where 

 its upper margin is suddenly cut out, in a semilunar manner, to 

 articulate with the suborbital chain, the anterior extremity passing 

 forwards below the orbit in a fine point towards the premaxillary, 

 which seems to be well developed, though its exact configuration is 

 not seen. Above the superior margin of the maxillary may be seen 

 a small narrow plate, pointed behind, and covering what remains of 

 the cheek in front of the opercxilum" and hyomandibular. This is 

 the preoperculum [p. op.) ; the corresponding plate in Palceoniscus is 

 determined as such by Quenstedt,' and, comparatively small as its 

 dimensions are, it certainly occupies a relative position similar to 

 that of the great preopercular cheek-plate of Polypterus. The oper- 

 culum (op.) is rather narrow, though broader above than below; its 

 posterior inferior angle is acute. Below it is seen a small nearly 

 quadrate suboperculum (s. op.). I am equally unable with Dr. 

 Young to find any trace of inter operculum. The lower jaw (ran.), 

 whose separate elements it is impossible to define, is stout in its pos- 

 terior half, but tapers to a point anteriorly; the symphysial extremity 

 is slightly turned up. Its external surface is marked with beautiful 

 short ridges and tubercles. The hrancMostegal rays (br.) are many 

 and enamelled, forming a series of little oblong plates, extending 

 from the suboperculum on each side between the rami of the lower 

 jaw. 



Teeth. — The teeth, with which the margins of both jaws are 

 armed, are small, smooth, conical, and sharp-pointed, with apex slight- 

 ly curved inwards. They are of two sizes, "large" and "small"; in 

 ordinary specimens the large ones measure about a-Vth inch in length, 

 and the others, very minute, are clearly seen in one specimen to 

 occupy a more external position on the edge of the jaw. I have not 

 had an opportunity of examining their microscopic structure ; but, 

 according to Messrs. Hancock and Atthey,^ their apices present the 

 same peculiar " enamel-cap " seen in the teeth of the allied forms 

 Palceoniscus, Pygopterus, etc., and also in those of the recent Lepido- 

 steus and Polypterus. 



SJwulder girdle. — The elements of the shoulder girdle are very 

 distinctly seen. The 1st supra-clavicular {supra-scapular Owen, 



^ Handbuch der Petrefactenkunde, Tab. 18, fig. 3. 

 2 Op. cit. p. 362. 



