NO. 1366. OSTEOLOGY OF BERYCOID FISHES— STARKS. 611 



upper surface of the pterotics. Anteriorly they do not project beyond 

 the ethmoid. Between their anterior ends there is a large pit for the 

 reception of the premaxillary processes. On their upper surface, 

 behind the eyes, the}' are armed with stout, smooth, radiating ridges, 

 each ending in a spine posteriorly. The epiotic has a large articular 

 facet, for the accomodation of the post-temporal, projecting laterally 

 to a point. The opisthotic is entirely inferior, presenting a nodule to 

 the lower limb of the post-temporal. The basisphenoid sends a very 

 long, strong process down to the parasphenoid. The alisphenoids 

 meet at the median line. The orbito-sphenoids meet at a right angle 

 and are fused into a solid plate, which has a small slit through its 

 middle. The parasphenoid sends out a long lateral wing on each side, 

 below the orbital cavit}. Behind the basitemporal wings, which it 

 sends up to the prootics, is a small opening into the m3'odome. Pos- 

 teriorly it ends in a point without reachmg to the occipital condyle. 



Fig. 8. — HoLocENTRus a.sce.nsiums. 

 For lettering .see fig. 6. 



The prefrontals are nowhere in contact, the ethmoid projecting both 

 before and behind them. The olfactory foramen is between the 

 ethmoid and the prefrontal, each bone forming a))out half of it. The 

 nasals are about twice as long as wide, projecting far over the ethmoid, 

 leaving an olfactory' chamber beneath. At each side there is a small, 

 curved, auxilary nasal, which arches awav from the base of the nasal 

 on the prefrontal and joins it again at al)out the middle of its outer 

 edge, inclosing a round space (probably the nostril). The same bone 

 is present in 2Iyripristis. 



FACE BONES. 



The opercular bones all have smooth ridges, each ending in a small, 

 sharp spine. The preopercle is scarcely channeled. The hyoman- 

 dil)ular has a divided head. There is a small opening between the 

 metapterygoid and the hyomandibular. The former has a very slight 

 outer wing developed. The symplectic is large and bent to conform 



