178 



Mr. C. T. Regan on the Osteology and 



common except the depressed head, and tlie skeletons show- 

 that the two genera are not at all closely related. Whereas 

 in Platijcephalus the roof of tlie myodome is ossified and the 

 basisphenoid is absent, in HopUchthijs the myodome has no 

 osseous roof, but the basisphenoid appears as a vertical 

 lamina between frontals and parasphenoid. In Platijcephalus 

 the suborbitals are on the upper surface of the head and are 

 separated by a wide interspace from the lower limb of the 

 preeoperculum, but in HopUchthys the suborbitals are angu- 

 lated, belonging partly to the upper and partly to the lower 



Fig. 3. 



A B 



Pectoral £n skeleton of A. HopUchthys langsdorfii, 

 B. Platycephalus insidiator, 



cl, cleithrum ; sc, hypercoracoid ; cor, hypocoracoid ; 1, 2, 3, 4, radiala. 



surface of the head, with a serrated ridge along their middle 

 at the edge of the head ; they entirely till the space between 

 the orbit and the prseoperculum. The palatine and pterygoid 

 form a long slender rod ; there is no mesopterygoid and the 

 metapterj'goid is reduced, so that the upper edge of the 

 quadrate is free. The upper fork of the post-temporal is 

 laminar, loosely attached to epiotic and pterotic ; the supra- 

 cleithrum is a slender rod ; the hypocoracoid is very narrow, 

 adherent to the cleithrum ; the four radials are anvil-shaped, 

 as in the Hexagrammidse and Scorpsenidse, but tiie interradial 

 foramina are closed by an osseous membrane (tig. 3, A). 



