The lo'.vemost portion of the tidal zone was us^jall;^ occupied by larger gastro- 

 pods, anong which the nost coiispicuoTis vrere Fasciolar ia princeps So^ier'by, Malea ringens 

 (Sv/ainson) , Cynat i vm tigrinum , Tritoaalia dioraedaeus Dall, Vasun caestus (Broderip) , 

 G-a leodes -oatula Broderip, Stron'ous pe ruvianus (S;fainson) , Murex ( Phylloaotus ) princeps 

 Broderi'o, and Mvirex ( Plyllonot'as ) regi us Sov/er-oy. The color of the inner smrface of the 

 shell of Miirex regius varied from faintly pink to red. In certain places (Stations lU, 12, 

 2o, and 27) great niar.oers of large G-aleodes patiila (Broderip) , Murex ( Phyllonotus ) nigritus 

 (Philip-oi), and Melongena p attila Broderip v;ere found in broken rocks scattered over the 

 tidal flats. This typical conimunlty of large gastropods extended helow low-v/ater level 

 (Fig. 15), pud v/as freo^uently encountered at many other stations. 



Algae were almost absent in the tidal zone. With the exception of Halicystis si 

 covering the hottoi's of snail tidal pools, and occasional occurrence of Galaxaura rugose 

 (Ellis and So lander) , Lsnoureux, juvenile plants af Padlna sp. , and snail pieces of 

 lithothannion sp. , the rocks were devoid of algal growth. Only at Isla de Uina (Station 6) 

 and Punta Pajaron (Station 2U) , the large areas of rocky shores were covered with the brown 

 and slippery carpet of Sp;i'"ridia aculeata (Schimp) J. Ag. and Galaxaura sp. In both places 

 I found great number of Galeodes patula . Dead shells of this large gastropod v/ere abundant 

 in nany places, v.'hile live snails v;ere found only on rocks below lov; water. V/ithin the 

 tidal zone, live specimens of this species were found only at the tv;o stations mentioned 

 above. 



.-^ii^ai^ 



Figure 15 Rocks along the shores of Isla Santelno, low tide. White spots on the top 



of central rocks are the dropt)ings of egrets and pelicans, v;hich abound 

 along the shore. Large gastropods ( Galeodes , Jasciolaria ) are very common 

 betvfeen the rocks. 



2/ Identified by Dr. Wra. R. Taylor of the University of Michigan. 



26 



