277 
of Edinburgh, Session 1876-77. 
Troschel in 1857,* the latter author using this character to separate 
the striated-scaled “ Amblypteri ” of Saarbriicken and Lebach, 
under the name of Rhabdolepis (i?. macropterus , R. eupterygius) 
from their smooth-scaled associates with minute slender teeth, for 
which the term Amblypterus was retained (A. latus , A. lateralis). 
An examination of the type-specimens of Elonichthys in the 
Mineralogical Museum at Halle has, however, convinced me that 
the genus is tenable, and that to it is referable an extensive series 
of Paheoniscidae, which will include, besides Giebel’s originals 
and several new species, various forms referred by Agassiz and 
other writers to Amblypterus , Palceoniscus, and Pygopterus. Several 
species also, whose position, from want of sufficient information, is 
somewhat doubtful, may best be placed here provisionally. 
Elonichthys most closely resembles Acrolepis and Bhabdolepis , 
but differs from the former in the anterior covered area of the scales 
being reduced to a very narrow margin, and from the latter in the 
absence of the subopercular plate. From Amblypterus , as restricted 
by Troschel, the greater obliquity of the suspensorium, and the 
dentition, are obvious marks of distinction ; the teeth in the 
true Amblypteri being minute, slender, without differentiated lani- 
aries, and more meriting the title “ en brosse” than those of any 
other genus of Palaeoniscidae. From Palceoniscus it is distinguished 
by the large size of the median fins, and by the possession of large 
conical teeth in the jaws, the teeth of Palceoniscus , as that genus 
must now be restricted, being small, and though, of different sizes, 
without conspicuous laniaries. It is also widely separated from 
Pygopterus by the structure of the pectoral fin, in which the prin- 
cipal rays are articulated for the greater part of their length, where- 
as in the last-named genus, they are unarticulated till towards their 
terminations; by the position of the dorsal fin, which, in relation 
to the anal, is further forward ; and by the form of the anal, which 
is not produced backwards in a fringe-like manner along the lower 
margin of the body. 
Accordingly Amblypterus nemopterus of Agassiz, and one of the 
two species included in his A. punctatus , must be transferred to 
Elonichthys , as well as his Palceoniscus Robisoni, P. striolatus , P. 
Egertoni , and Pygopterus Bucklandi. The mutual resemblances of 
* “Verh. des naturhist. ver. d. preuss. Rheinlande,” xiv. (1857) p. 12. 
