1S7U.J ^^'^ [Cope. 



ANCHYBOPSIS. Cops. 



Genus novum. 



This form, characterized above, is nearly related to several now exist- 

 ing in the rivers of the United States, so far as the i^haryngeal teeth 

 serve as an indication. It is well known that they are more significant 

 than any other part of the skeleton among the Cyprinidse. They are 

 arranged in one series of five on the right side, which rises and stands on 

 a prominent basis superiorly, as in various genera, as Stilbe, most Hy- 

 bopses, etc. This prominence is due to the abrupt incurvature of the 

 superior limb of the bone. The crowns of the teeth are compressed, the 

 grinding face truncate a little obliquely, and with a slightly concave 

 transverse worm surface. Proximal limb small. 



In Hybopsis the teeth are 4-4, but in Hemitremia Cope, 5-4, and quite 

 similar to those of this genus. In Hemitremia, however, the lateral line 

 is incomplete, and coincidence in this point is necessary for the reference 

 of the present form to that genus. Imperfection of the lateral line is 

 not known among the larger forms of true Cypriniclge on this continent, 

 and may not have existed in this genus. The principal ground of sei^a- 

 ration from Hemitremia is found in the transversely compressed and very 

 short crown of the teeth ; in the latter they are elongate and subcylindric. 

 Anch.yhopsis is a more typically herbivorous form, and probably had 

 much convoluted intestines, while in Uyho^jsis they are of the short 

 carnivorous type. 



Anchtbopsis latus. Cope. 

 Spec. nov. 



The only species of the genus. The pharyngeal bone expands rather 

 abruptly into a prominent ala, without angular outline, and which soon 

 turns into the outline of the superior liml). Surface of ala with trans- 

 verse grooves to margin. Sizes of teeth 4, o, 2, 5, 1, the first smallest, and 

 with obtuse, subconic crown. Section of proximal limb at base of last, a 

 triangle with truncate apex directed outwards. Teeth directed inwards ; 

 nutritious foramina on front of bone numerous and large. 



3Ieasurements. M. 



Length tooth series ^ 0.02fi 



" third tooth ' Oil 



Long diameter crown tooth 0075 



Width bone at third tooth (exterior) 016 



(anterior) 016 



" ': first tooth (exterior) 006 



MYLOCTPEINUS. Leidy. 



Proceedings Academy ISTatural Sciences. Philadelphia, 1870, p. 70. 



This genus, named by Leidy, as above, had been noticed by Dr. J. S. 

 Newberry" as allied to Mylochilus, Agass. Leidy compares it to the 

 carp and other Cypriuoids. Its affinities are apparently between Mylo- 



* In Proceedings New York Lyceum Natural History, 1S70. Copied into Nature, 1S70, p. 385. 



