HO THURLOW C. NELSON. 



currents. Until extensive oceanographic investigations are 

 conducted along our coasts during every month of the year for a 

 considerable period, we shall continue ignorant of most of the 

 underlying factors which finally determine the abundance and 

 distribution of many of the transient visitors to our coastal 



waters. 



SUMMARY. 



The occurrence and distribution of the three ctenophores, 

 Mnemiopsis leidyi, Pleurobrachia brunnea, and Beroe ovata in New 

 Jersey inland coastal waters are considered as affected by factors 

 of the environment. 



Pleurobrachia was observed twice, Beroe during a few days for 

 three seasons, Mnemiopsis was seen daily for months at a time. 



Evidence is presented which indicates that all three of these 

 forms are casual visitors to the inland coastal waterways of New 

 Jersey. Beroe and Pleurobrachia are found here only after the 

 heat of summer is past, whereas Mnemiopsis appears in late 

 spring or early summer and flourishes until late autumn or 

 winter. 



The remarkable power of temperature adaptation of Mnemi- 

 opsis is shown by the fact that in individuals taken in the winter 

 the swimming plates continue to beat until frozen fast in the ice. 



The three ctenophores are shown to be able to withstand 

 salinities in the bays w r hich are considerably below those of the 

 ocean lanes from which the animals came. The conclusions of 

 Mayer and of Bigelow r in this connection are discussed. 



A study of the food habits of Mnemiopsis reveals the fact that 

 large numbers of bivalve larva? may be destroyed by them. 

 A distinct correlation is shown between the abundance of Mnemi- 

 opsis and the intensity of "sets" of oysters and of marine borers. 



BIBLIOGRAPHY. 

 Bigelow, H. B. 



'12 A Review of Mayer's Ctenophores of the Atlantic Coast of North America. 



Science. Aug. 23, 1912, p. 243. 



'15 Exploration of the Coast Waters between Nova Scotia and Chesapeake Bay, 

 July and August, 1913, by the U. S. Fisheries Schooner, Grampus. 

 Oceanography and Plankton. Bull. Museum of Comp. Zocil. Cambridge, 

 Vol. LIX., No. 4. 

 Hargitt, C. W. 



'04 The Medusae of the Woods Hull- Kr^ion. Bull. Bureau of Fisheries, Vol. 

 XXIV., p. 21. 



