185 



at the l)ase of which are one or more foramina. The postfrontal shares with 

 the pterotic the support of the hyomandibular. Tlie prootic is elongate, and 

 sends a crest downward and forward to the basis of the above-mentioned 

 j>rocess of the parasphenoid. Superiorly, it bounds, with tiie pterotic and 

 sometimes {Portheus) opisthotic, a large foramen. 



The pretnaxUlari/ hones are short, and form but a small j)ortion of the 

 upper jaw. The ma.villary is elongate and simple. The hyomandibular is 

 rather narrow, and does not ])rescnt an elongate support for the operculum. 

 The symj)lectic is well developed, entering fiir into the inferior quadrate. The 

 latter is a broad bone, large, in contact with the metapterygoid, which is 

 itself a thin plate, nearly attaining the pterotic. In Portheus, the pterygoid 

 is well developed as a Inoad plate extending to the inferior boundary of the 

 orbits. The palatine exhibits a marked peculiarity in the genera of this fam- 

 ily. It is a shortish bone, soon uniting postero-inferiorly with the ectoptery- 

 goid, but .supporting as its supero-anterior extremity a body comparable to 

 the head of a hammer. This malleolar body, as it may be called, is a short- 

 ened cylinder, with one extremity articulated to the prefrontal and the other 

 to the posterior superior of the maxillary facets. This gives the latter bone 

 a firnmess of support unusual among fishes. It also probably permits, 

 of .some movement of the maxillary in a horizontal plane, which, thougli 

 small, would have the effect of considerai)ly expanding the gape of the 

 mouth, tluis enabling tliese fishes to swallow large bodies, in the manner 

 of the Mosasauroids of the same sea and epoch. 



The ectopterygoid is a large bone, and extends down on the front of the 

 inferior quadrate. Neither it nor the palatine supports teeth in any of the 

 known genera. 



The sclerotica of (he eye is ossilied in Portheus and Ichthyodectes. This 

 cssificatiou does not cover tlie eye, is not a complete circle, and is unseg- 

 mented. 



Little can be said respecting the hyoid apparatus in this family. Some 

 superior branchihyals, preserved in Portheus thaumas, are short flat rods. 

 Two long llat bones, in place between the dentaries of a P. lestrio, a[)pear to 

 be the distal ceratohyals. They terminate in some crushed basihyals, and are 

 covered with minute teeth en brosse on the inner faces and superior margin.s. 



No specimen exiiibits the entire scapular a?-ch, but several preserve the 

 scapula witii adjacent parts; two, a Portheus and probably an Ichthyodectes, 



