234 THE AMERICAN NATURALIST. | [Vor. XXXIV. 
ing strychnine) has been found very useful in killing the fishes of 
these pools, often not to be captured in any other way. Mr. Greeley 
found a good substitute for this poison in the commercial chloride of 
lime. D. S. J. 
. Development of Brain Structures in Amia. — A. C. Eyclesheimer 
and B. M. Davis give in the Journal of Comparative Neurology a 
valuable study of “The Early Development of the Epiphysis and 
Paraphysis in Amia.” The paper indicates that much is still to be 
known as to the origin of epiphysial outgrowths from brain structures. 
b. sd 
Scapanorhynchus and Mitsukurina. — In the Annals and Maga- 
zine of Natural History, Mr. A. S. Woodward, of the British Museum, 
has a note on Mitsukurina owstoni Jordan, an extraordinary lamnoid 
shark with a long flat blade on its snout, lately described from the 
deep waters of Japan. 
Mr. Woodward shows that Mitsukurina is very closely related to 
the Cretaceous genus Scapanorhynchus, of which species are known 
from Mount Lebanon and from the chalk of England. 
Mitsukurina and Scapanorhynchus agree in the elongate, blade- 
like snout, which is, however, longest in Scapanorhynchus. The 
skeleton, dentition, and gill openings seem to be similar in the two 
genera, and there appear to be no great differences in the fins. 
The dense shagreen is also similar in the twó ; the structure of the 
basal cartilages of the fins in Scapanorhynchus is unknown ; nor is 
anything known of the claspers. 
Mr. Woodward concludes that Mitsukurina is probably identical 
with his genus, Scapanorhynchus, this name being of prior date. 
On the other hand, it may be urged that this identity is not proved, 
and that the specific differences are considerable. There are great 
disadvantages in the identification of recent fishes with fossil genera 
which are more or less imperfectly known. 
More complete knowledge of the extinct forms often shows that 
the recent species have undergone such differentiation as should 
constitute generic difference. I think it, therefore, better to retain 
for the recent shark the name Mitsukurina, although recognizing its 
` close relationship to its Cretaceous homologue. 
The family Mitsukurinidz is supposed to differ from Carchariidze 
(Odontaspididz) in the presence of a Polyodon-like snout, and per- 
haps in the structure of its fins and claspers. The writer knows too 
