Dr. C. R. Eadman — New Form of Shark's Dentition. 151 



Description of Campylopbion annectans, gen. et sp. no v. 

 (PI. VIII, Fig. 2 ; and Woodcut, Fig. 3, in text.) 



In the same category with Edestus and Helicoprion must be 

 placed a new genus of Paleozoic Cestracionts, known as yet only 

 by its syraphysial dentition, for which the name Campyloprion is 

 proposed, with the type species of C. anneclans. This is founded 

 on a unique specimen belonging to Tufts College Museum, Boston, 

 the description of which follows. The new genus is also held to 

 include two species originally assigned to Edestm, namely, E. davisii, 

 Woodward, and E. lecontei, Dean. The former of these has been dis- 

 cussed in its relations to other Edestus-Uke structures by Woodward, 

 Dean, and Karpinsky, and was transferred by the last-named author to 

 Helicoprion. For the sake of comparison we may briefly summarize 

 the distinguishing characters of these four closely related genera, as 

 follows : — 



1. Campodus. — Auterior series of thirteen or more teeth fused into a semicircular' 

 arch, their outer (anterior) coronal margins prominently buttressed, and their 

 coronal apices rather obtuse and not serrated ; the teeth only slightly overriding one 

 another at their extremities, not much laterally compressed, and very much larger 

 than the immediately adjoining lateral series, which also have their buttresses 

 directed outward. Type, 0. agassizianus, Koninck. 



2. Edestus. — Auterior series of seven or more fused teeth only moderately arched 

 and laterally compressed ; coronal apices acuminate and serrated along the sharpened 

 anterior and posterior margins ; bases strongly reflected forward, invaginated, and 

 fused throughout. Lateral series unknown. Type, E. vorax, Leidy. 



3. Campyloprion. — Anterior series of twenty or more fused teeth considerably 

 arched and much laterally compressed ; coronal apices rather obtuse, and coarsely 

 serrated along the sharpened anterior and posterior margins ; teeth curved or bent 

 forward, overriding one another toward their extremities and fused for the greater 

 portion of their length. Type, C. annectans, sp. nov. 



4. Helicoprion. — Anterior series consisting of upwards of 150 fused teeth, very 

 similar to the last in form, but coiled into approximately 2>\ whorls ; coronal apices 

 acute and finely serrated along the sharpened anterior and posterior margins ; enamel 

 extending far down the lateral faces ; teeth more or less strongly curved forward, 

 overlapping and fused for a portion of their length ; two lateral grooves extending 

 along the spiral near the bottom. Lateral series unknown. Type, S. bessonowi, 

 Karpinsky. 



Arranged in the above order we are enabled to note the pro- 

 gressive stages by which the typical Cestraciont dentition of Orodus 

 and Campodus, occurring in the Carboniferous, passed into the 

 excessively modified spirals of Helicoprion in the Permian. Moreover, 

 the chief interest attaching to Campyloprion is on account of its 

 intermediate position, two of its species linking it with Edestus, 

 as already observed, and a third, as denoted by its trivial title, 

 marking the ti'ansition to Helicoprion. 



For the opportunity to describe the interesting series of teeth 

 shown in Plate VIII, Fig. 2, and section in text. Fig. 3, the writer is 

 indebted to his friend Dr. J. S. Kingsley, of Tufts College, in whose 

 custody it has been for many years. Unfortunately nothing is known 

 of the history of the specimen prior to its coming to Tufts, except 

 that it was procured for the Museum by the late Professor Marshall. 

 While its age may be confidently attril3uted to the Upper Carboni- 

 ferous or Permian, there is no clue as to its locality. The specimen 



