placed, most commonly almost completely filled by a black substance. 

 The particular elements of the neurocranium cannot be distinguished, 

 since as a rule the bone boundaries are not indicated. Hence, only the 

 general contour of the skull is shown in Fig. 7. 



OS. infr 



nyorndb 



Gntptr 



porsph 



prmax 



Fig. 7. Eomyctophum menneri DaniL, skull (after specimen No. 17 Os.); ca x 8.6. 

 dent, dentary, ectptr. ectopterygoideum, entptr. entopterygoideum, hyomdh. 

 hyomandibulare, krthy. keratohyale, mtptr. metapterygoideum, max. maxillare, 

 op. operculum, os. injr. ossa infraorbitalia, p. pigment, parsph. parasphenoideum, 

 prop, praeoperculum, pp. alimentary canal, pr. k. osseous rods, prmax. praemaxi- 

 llare, Q — quadratum, r. hr. radii branchiostegii, w. f. filtration process, I — IV 

 gill arches, V probably an element of 5th gill aicha. 



A long, narrow, premaxillary bone which rims the upper border 

 of the snout is very clearly indicated within the cranium viscerale. 

 The long, narrow maxillary bone overlies it. On many specimens mi- 

 nute, densely spaced denticles occur on the premaxillary bone and on 

 the long, strongly developed dentary of the lower jaw. The mouth 

 opening of all species reaches beyond the posterior border of the orbit. 



In our material, the skeleton of the gill apparatus is represented 

 by fragmentary remains of the gill arches. On these are very distinctly 

 seen osseous rods which support the gill lobes (Fig. 7), and relatively 



22 



