THE HYDROIDS. 



INTRODUCTION. 



The collection of Hydroids made by Mr. Agassiz in the Eastern Pacific 

 in 1904-1905 is a small one of twelve species, and some of these are repre- 

 sented by single specimens. All of them are from the tropics, four are from 

 the shores of Perico Island in the Gulf of Panama, three are from stations 

 near the Galapagos Islands, two are from stations off Aguja and Callao, 

 Peru, and one, Ohelia striata, was also collected in the open Pacific almost 

 directly on the equator, some 1500 miles west of South America. Their 

 names, localities, and bathymetrical distribution are shown in the accom- 

 panying table : — 



Peuuaria paciflca, sp. nov. 

 Campanularia obliqua, sp. nov 

 Obelia striata, sp. nov. 

 Obelia striata, sp. nov. 



Obelia sp 



Campanulina deuticulata, sp. nov. 

 Lafoea gracillima 

 Thuiaria tubuliforinis . 

 Sertularella tropica . 

 Zygophylax ehazaliei . 

 Cladocarpus distomus, sp. nov. 

 Plumularia helleri . 

 Pluinularia helleri . 

 Aglaophenia struthionides 



Station No. 



Perico Id. 

 Perico Id. 



4742 



4657 

 Perico Id. 



4672 



4642 

 Perico Id. 



4647 



4642 



4630 



4621 



4622 



4643 



Latitude. 



N. 

 S. 



s. 

 s. 



s. 

 s. 



N. 

 N. 

 N. 

 S. 



0° 3.4' 

 7 12.5 



13 11.6 

 1 30.5 



4 33 



1 30.5 



6 52.0 



6 36.0 



6 31.0 



1 28.7 



Longitude W. 



Depth. 



117° 15.8' 



84 9.0 



78 

 89 



87 

 89 

 81 

 81 

 81 

 89 



18.3 

 35.0 



42.5 

 35.0 

 42.5 

 44.0 

 44.0 

 48.5 



Trawl 2320 

 Tow 300 



2845 

 300 



2005 

 300 

 556 

 581 

 581 

 100 



The most surprising fact about this collection is that from the 116 

 stations occupied on this expedition the hydroids are so small in amount 

 and the species so few. From the shores of Perico Island, near the anchor- 

 age of the " Albatross," in the Bay of Panama, there are four species, and 

 the remaining seven are from eight of the stations after leaving Panama. 

 That leaves 112 stations showing no hydroid life. Of the eleven species, 

 Lafoea gracillima is the most widely known, but it has hitherto been re- 

 ported from northern waters only ; Marktanner-Turneretscher 79° 5.4' N. 



