Cope.] ^^^ [Dec. 2, 



illary bone mucli prolonged, sub-cylindric, but little compressed distally, 

 bearing reduced teeth near its extremity. Preorbital bone short, sub- 

 orbital narrow. Inferior basihyals as deep as long. 



This genus is nearlly allied to Salmo. With no other portions of the 

 animal than the cranial bones, the only difference I discover is in the 

 form of the maxillary bones, which are subcylindric or rod-like, instead of 

 flat or laminiform, as in Salmo. At the extremity, though flat, they are 

 still narrow, and I do not find surface of attachment for the supernumer- 

 ary bone of Salmo. 



Rhabdofakio lacusteis. Cope. 



Species nova. 



This fish is repi-esented by a large part of the cranium, including all 

 anterior to the middle of the orbits above, to the metapterygoid medially, 

 and to the posterior part of the dentary below. Both dentaries remain, 

 but the premaxillary and maxillary of one side only are preserved. There 

 are separate portions of the maxillary bone, of four other individuals, and 

 mandibular and palatine of one. These indicate a salmon of the average 

 size of the migratory marine species, Salmo salar. 



The cranium has been compressed, bu.t apparently not depressed, so 

 that the plane of the muzzle from the frontal bones is perhax)s nearly pre- 

 served. In its present condition the profile descends very gradually, and 

 the muzzle has an acuminate form. The frontals are ornamented by 

 numerous grooves which radiate anterioily, and are more numerous me- 

 dially. The premaxillaries are subvertical, or roof shaped, and their 

 broad lateral face is prolonged well backwards^to opposite the fifth 

 mandibular tooth. The distal part of the maxillary and the dentary are 

 striate-grooved, the latter obliquely downwards. The extremities of the 

 dentaries are rugose, and emarginate in profile. They are not produced 

 or recurved at the symphysis, and the latter is not coossified in the speci- 

 men. The anterior extremity of the premaxillary is lost, but the remain- 

 ing portion supports five teeth. There are seventeen on the part of the 

 maxillary preserved, three inOM.Ol. There are 14-15 on the dentary, 

 two in M.Ol. The palatine, vomerine and the glossohyal teeth are a 

 little smaller than the dentaries, and more as the maxillaries. All the 

 teeth have swollen bases, with a plurodont attachment. The crowns are 

 cylindric, acute, and on the latei'al bones, incurved. 



Measurements. M. 



Length of the tooth series of the dentary .093 



Depth of symphysi 018 



Depth pterygoid and palatine at last mandibular tooth 027 



Depth premaxillary at middle 018 



Length crown of a mandibular tooth 008 



Width of half frontal bone at nares 014 



" suborbital 0085 



The preorbital region is occupied by a bone somewhat T-shaped, the 

 vertical limb spatulate, directed downwards and forwards, with grooved 

 margins. Suborbital with rough marginal face. 



