JVb. 6. — Bepoi'ts on the Dredging Operations off the West Coast of 

 Central America to the Galapagos, to the West Coast of Mexico, 

 and in the Gulf of California, in Charge of Alexander Agassiz, 

 carried, on hy the U. S. Fish Commission Steamer " Albatross" 

 during 1891, Lieut. Commander Z. L. Tanner, U. S. K 

 Commanding. 



[Published by Permission of Marshall McDonald, U. S. Fish Commissioner.] 



X. 



The Hydroids. By Samuel F. Clarke. 



The Hydroids of this collection are from off the west coast of Central 

 America. All but one are from the southward of the city of Panama, 

 about one hundred to one hundred and forty miles, and from one other 

 point about one hundred and seventy-five miles southwest of Panama. 



The records of the various stations where the specimens were taken, 

 are as follows : — 



The species are ten in number. 



GYMNOBLASTEA. 



Eudendrium, sp. 



CALYPTOBLASTEA. 

 Campanularia castellata, sp. nov. 

 Lafoea convallaria, Allman. 

 Lictorella geniculata, sp. nov. 

 Halecium argenteum, sp. nov. 

 Halecium gracile, R.\le. 

 Sertularia variabilis, sp. nov. 

 Cryptolaria conferta, Allman. 

 Cryptolaria pulchella, Allman. 

 Plumularia helleri, Hincks. 



VOL. XXV. — NO. 6. 



