574 Proceedings of Societies. [ September, 
tennial Exposition, for which the name Proroziphius conops was pro- 1 
posed. A fragment of a skull of Squalodon from the same collection í 
was also exhibited. The remarkable admixture of fossils of different 
geological ages in these deposits was again alluded to. 
A tooth of a Megalodon shark, measuring six and seven tenths 
inches long, was described, and the opinion advanced*that, comparing it . 
with teeth of existing sharks, it probably had belonged to an individual 
upwards of one hundred feet in length. ` ; 
Professor Cope recorded having seen remains of a cretaceous verte- : 
brate from the deposit spoken of by Dr. Leidy. It belonged to the : 
sixth genus of the order Pythonomorpha and was described under the 
name of Cyclotomodon vagrans. 
Professor Cope also exhibited and described a fossil fish from the cre- 
taceous formation of Nebraska. The structure of the mouth was that 
of the soft-rayed fishes, and the other characters ally it to the group to 
which belong the mullets. The dentition and the structure of the caudal 
fin were described and the name Anogmius aratus was proposed for the 
form. : 
CALIFORNIA Acapemy of Sciences, San Francisco.— April 34, 
Professor Davidson read the first of his series of papers on irrigation, 
harbors, and engineering in Europe and Asia, giving the results of per 
sonal observation. The paper was devoted to Indian irrigation, and was 
rich in interesting details, and in the value of its conclusions applied to 
the necessities of artificial water-courses in California. The lecturer 
said that the Indian canals had not paid private capital, and the expense 
had been assumed by the government, which is projecting and building 
a magnificent system of irrigating works. 
Dr. Hale, a visitor, related an instance of “ mimicry » which he ob- | 
served in the Santa Cruz Mountains. It was a milk-white spider, : 
shape, size, and color the exact counterpart of the flower Medrono; E 
April 18th. Captain Bryant, United States Treasury Agent, who 8 
stationed on the Aleutian Fur Seal Islands, was present, and gave # 
brief history of the habits of the seals and the manner in which they #9 
caught. Notwithstanding the slaughter of one hundred thousand annually 
by the Alaska Commercial Company, the legal limit under the company § 
lease from the hational government, a careful calculation 5 
seals are increasing, as compared between the year 1869 and the past 
season, five per cent. in number. The revenue of the government from 
this source is $325,000 per annum, being nearly five per cent. on the : 
amount paid for the territory of Alaska. : 
Boston Society or NaruraL History. — June 7th. Commune 
tions were read by Dr. W. K. Brooks on The Separation of the Sexes 
Salpa by means of Natural Selection; by Professor A. Hyatt on iy 8 
among the Ammonites of the Oölitic Formations; and by Mr. Wi V 
Crosby on the Geology of Eastern Massachusetts. 
