EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA I 2 I 



frontal lobe and specially on the anterior half of the limb. Frontal lobe 

 laro-e, transversely subrhomboidal ; the other three pairs of lobes distinctly 

 separated. Eyes large with grooved bases, sutural furrow on the cheek 

 deep and smooth. Frontal border moderately broad, slightly concave, 

 smooth and entire. This type of cephalon conforms closely to that of 

 D. hausmanni which stands as the type of the subgenus Hausmannia 

 Hall & Clarke, probably equivalent to Odontochile. It is an archaic type in 

 the sense that it prevails in the late Sikiric, nearly all fully developed 

 Devonic Dalmanites except Cryphaeus showing a fusion of adjoining lateral 

 lobes, which is distinct in character from the lobal fusion present in Chas- 

 mops, Monorachus and Pterygometopus of the' Lower Siluric. In minor 

 differentials there is no distinction between the Grande Greve specimens and 

 the cephalon of this species as found in the Coeymans limestone, save that 

 in the former the median depression on the frontal lobe is more pronounced, 

 the granulation is coarser and on the cheeks the granules show a tendency 

 to fusion. 



Dhnensions. Axial length 24 mm ; width across the base 47 mm. 



There are some small pygidia which have the general type of that of 

 D, micrurus, agreeing therewith in form and in the character of the 

 flattened faintly grooved ribs and in the short caudal spine. The original 

 of this species has 14-15 lateral ribs and 15-16 axial, while the Grande 

 Greve specimens have but 10 lateral and 13-14 axial. If these tail shields 

 actually belong to the cephalon described they indicate a slight variation 

 from the New York type. Among these shields themselves there is appar- 

 ently some slight difference in the length of the caudal spine. 



Localities. From the middle horizon of the limestone near Indian Cove 

 and Lehuquet's Cove. 



Dalmanites dolbeli nov. 



Plate 8, figures 1-7 



cf. Dalmanites p 1 e u r o p t y x Logan. Geol. Can. 1863. p. 393 



Certain cephala and pygidia of these beds which there are good reasons 

 for assigning to each other present many points of resemblance to several 

 well known species of the same subgeneric type. The latter are D. p 1 e u - 

 roptyx of the New Scotland beds (Helderbergian), D. stemmatus of 

 the Oriskany and D. anchiops of the Schoharie grit. Generally speak- 

 ing these four species are alike in the following respects : They are all 

 forms which attain a large size, have notably short and broad cephala, with 

 the first and second glabellar lobes fused distally and elevated to the eye 

 lobe, frontal border with a row of crenulations at the edge, the more con- 

 spicuous being terminal, grooved eye base, faint if any groove along the 

 lateral facial suture, and inosculating surface markings on the cheeks. The 

 tails are broadly triangular and sparse ribbed ending in caridal spines not 

 greatly extended. 



