OSTEOLOGY' OF CAULARCHUS M.EANDRICUS (G1RARD). 293 



parietal region by a low transverse ridge. Long lateral proc- 

 esses from the prefrontal and sphenotic bound the orbital region. 

 Broad wings from the sides of the parasphenoid form a wide 

 floor anterior to, and in continuation with, the floor of the brain- 

 case. The basisphenoid and opisthotic are absent. There is no 

 myodome. In Gobiesox the anterior portion of the cranium is 

 scarcely depressed for the reception of the premaxillary processes. 



The basioccipital is a flat bone not turned up at its lateral 

 edges, and the greater part of it is covered by the wide para- 

 sphenoid. Its condyle is depressed, ellipitical in shape, and slightly 

 inclined upward in opposition to the exoccipital condyles which 

 are slightly inclined downward. 



The exoccipitals are widely separated by the interposition of 

 the basioccipital between them. They assist the latter bone in 

 connecting the cranium with the vertebral column, presenting a 

 round condyle at each side of the basioccipital condyle, so that 

 the three parts of the basioccipital condyle are on a horizontal 

 line. 1 



The surface of the supraoccipital is divided into two parts by 

 the meeting of the parietals over its middle. The visible anterior 

 portion of the supraoccipital thus separated from the posterior 

 portion is nearly round in outline. In a few of the specimens 

 examined the parietals just touch, in none of them do they meet 

 broadly. In Gobicso.v the parietals are well separated by the 

 supraoccipital, extending over the edge of the latter only slightly. 2 



1 The condyles of the exoccipitals are wholly lateral to that of the basioccipital only 

 in those fishes with a much depressed form, as Callionymus, .Rernora or Catilarchns, 

 though it does not at all follow that all fishes with depressed forms have lateral 

 occipital condyles. It appears to be the rule that fishes with a depressed form never 

 have the condyles of the exoccipitals wholly superior and in contact wiih each other, 

 while those with a compressed form never have them wholly lateral. 



? -The condition of the meeting of the parietals should be more fully reported upon 

 in other forms. Their union or separation by the supraoccipital has been used in the 

 past in distinguishing large groups, and though the character has doubtless much less 

 value than has been ascribed to it, its real value can not be known until it is more 

 fully investigated. The difference between the condition of the parietals in Caularchus 

 and Gobiesox is but a difference in degree where in one form they develop over the 

 supraoccipital a little further than in the other and meet. This condition obviously 

 has not the importance it has in some of the cyprinoid fishes where the parietals meet 

 broadly entirely in front of the supraoccipital, and are the roof bones of the cranium 

 in this region. The brief statement " parietals meeting" or " parietals separated by 

 the supraoccipital " is far from being adequate. The condition of the parietals in 

 Ciiu/arc/tus is not a very unusual one. 



