Zoological Society bulletin . l in size to the European lobster. The crayfish has many natural enemies. Per-haps the most destructive are various species offishes, the larger salamanders, such as the mud-puppy (Necturus) and hellbender (Crypto-branchus) and water-snakes. No doubt thesemi-aquatic mammals take their toll and theraccoon is said to be particularly fond of aquatic birds feed upon them. They areparasitized by leeches, copepod crustaceans andworms. The shells are often overgrown withdiatoms and algae, and those from our parklakes are often covered with a profuse growthof a
Zoological Society bulletin . l in size to the European lobster. The crayfish has many natural enemies. Per-haps the most destructive are various species offishes, the larger salamanders, such as the mud-puppy (Necturus) and hellbender (Crypto-branchus) and water-snakes. No doubt thesemi-aquatic mammals take their toll and theraccoon is said to be particularly fond of aquatic birds feed upon them. They areparasitized by leeches, copepod crustaceans andworms. The shells are often overgrown withdiatoms and algae, and those from our parklakes are often covered with a profuse growthof a large colonial protozoan (Epistylus). Itis doubtful if these do any particular harm, ex-cept, perhaps, to impede the progress of thecrayfish when the growth is abundant. Fur-thermore, all crayfishes are given to cannibalismto some extent, and not onby are young devouredby the adults, but full-grown specimens, whenshedding, may be attacked and devoured beforethe new shell has had time to harden enough toserve for a American Xaturalist, May, Contributions to Knowledge, 1907. CRAYFISH COVERED WITH PROTOZOANSOne-half natural size. Photograph by H. C. Osburn. 928 ZOOLOGICAL SOCIETY BULLETIN. ZOOLOGICAL SOCIETY BULLETIN. Mammal w. T. Hornaday- Aquarium C. H. TOWNSEND. ^Departments: ReptileRaymond L. Ditmars. BirdC. William Beebb. Raymond C. Osburn. Lee S. Crandall. Published Bi-Montb]y at tbe Office of the Society,11 Wall Street. New York City. Yearly, by Mail, MAILED FREE TO MEMBERS. Copyright, 1912, by the New York Zoological Society. Each author is responsible for tbe scientific accuracyand the proof reading of his contribution. Elwin R. Sanborn, Editor. Vol. XVI. No. 54 NOVEMBER, 1913 Minute adopted by the Executive Committeeof the New York Zoological Society, held onTuesday, the eighth of October, One thousandnine hundred and twelve. Resolved, That the Executive Committeelearn with deep regret of the death of J. Chisholm, a
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1901
