1891.] Geology and Paleontology. 479 
General Notes. 
GEOLOGY AND PALEONTOLOGY. 
On the Non-Actinopterygian Teleostomi.—Material is not at 
present accessible in the United States from which to learn the struc- 
ture of the median fins in the Holoptychiide and Osteolepidide. In 
drawing up my Synopsis of the Families of the Vertebrata, in 1889,! I 
assumed that these fins had the primitive structure, such as is found in 
the oldest members of the Teleostomi (Tarassiidze), Dipnoi, and other 
subclasses, viz., that the axonosts are equal in number to, and con- 
tinuous with, the neural spines of the Vertebrata. This definition 
threw the families in question into the Crossopterygia as distinguished 
from the Rhipidopterygia. In the latter the axonosts are much reduced 
in number, so that one or two fused into a single piece supports each 
dorsal and anal fin. 
Prof. Traquair has, however, stated that the dorsal fins of the 
Osteolepidide are of the Rhipidopterygian type, and Mr. A. Smith 
Woodward in the Volume II. of the Catalogue of Fossil Fishes in the 
British Museum? confirms this statement, and shows that the Holopty- 
chiidz agree with them in this respect. He does not adopt the super- 
order Rhipidopterygia, but combines it with the Crossopterygia ; and 
he places the families mentioned, together with the Rhizodontide, 
which is my Tristichopteridz, in the order to which I referred the latter, 
the Rhipidistia. As regards this ordinal reference, it is clearly neces- 
sary on the evidence brought forward by Traquair and by Woodward. 
I do not, however, see that the Rhipidopterygia can be properly com- 
bined with the Crossopterygia, since the structure of the median fins 
is radically different, and one which offers as good ground for super- 
ordinal distinction as do the paired fins offer ground for the separation 
of the Actinopterygia. The Tarassiida and the Polypteridz possess 
the characters of the median fins which I viewed as characteristic of 
the Crossopterygia, while the paired fins, so far as can be discovered 
from the descriptions of the former,’ indicate two distinct orders 
within it. 
? AMERICAN NATURALIST, p. 856. 
? L. c., 189%, p. 321 
3 Smith W: Wobduned: E c, IL, p. 317- 
