DAVIS: NOTE OX ( 'irL AM YDOSELACIIUS. 
99 
Selachians, in this, the frill or flap, covering the first opening- is free 
across the isthmus, as in fishes, and hangs down about half-an-inch. 
The nostrils are nearly vertical, with a fold dividing each orifice into 
two parts. The eyes are moderately large, on the side of the head, 
midway over the length of the mouth : there is no trace of nictitating 
membrane. The pectoral fins are of moderate size, and are 
separated by a distance of tw^o feet from the ventrals. The ventral, 
anal, and candal are lai-ge. Above the anal fin there is a small 
dorsal. At their margins the fins are ver}^ thin, and their extremities 
are produced in a sort of filament. The structure of the jaws and 
gill arches is such as to admit of swallowing a large object, at the 
same time the excessive sharpness of the teeth, and the small size of 
intestine, indicate that the prey is comparatively soft. The vertebrae 
and other cartilages are flexible, as those of the basking sharks, 
Selache and Somniosus. A certain embryonic appearance in the 
specimen instigated a search among the fossils for allied species. 
Most resemblance was found in the teeth of Cladodus of the 
Devonian : but the cusps were erect instead of reclining, and the ^ 
enamel vcas grooved instead of smooth. One is impressed by a 
study of this specimen with the idea that, away back in times ^\ hen 
selachia and fishes were more alike, he would have a better chance 
to trace the affinities. I am inclined to consider this the type of a 
new order, to which the name Selachophichthyoidi might be given, 
and which stands nearer the true fishes than do the sharks proper." 
After the publication by Mr. Garman of the above, somewhat 
superficial description, a considerable amount of correspondence 
took place in the pages of •* Science," and diverse opinions were 
expressed as to the relationship of the genus to extinct forms. Prof. 
E. D. Cope, on March 7th, considers that the teeth figured by 
Mr. Garman "shows the animal to be a species of the genus 
Didymodus (=^I)iplodus, Agass) w^hich has hitherto been supposed to 
to be confined to the Carboniferous and Permian periods," and in 
the " American Naturalist" of the following month, he confirms his 
opinion to a greater length, and states that the species should be 
called Didymodus anguineus. 
Prof. Theo. Gill, expresses an opinion that Chlamydoseluchus 
