NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 191 



terested in the marine algae. The general environmental conditions were 

 still unrecorded for the plants of this large area, and seasonal changes not 

 only had escaped investigation but had never been considered. Though 

 over a hundred species of algae were recorded from the Gulf, collection 

 localities were scattered, and the absence of winter collections suggested 

 strongly that further exploration would be very fruitful. 



Five weeks of cruising on the 195-foot twin Diesel Velero III allowed 

 us to make 90 collection-station records, from over half of which algal 

 material was obtained. The whole length of the Gulf was traversed, from 

 San Jose del Cabo, Lx)wer California, to Punta Pefiasco (Rocky Point), 

 Sonora. 



For the detailed analysis of this expedition, the cruise charts, and com- 

 plete station records, the reader is referred to Volume 1, nos. 1, 2, 3, of 

 this series. 



The splendid dredging equipment afforded by the Velero III permit- 

 ted the carrying out of extensive sublittoral collecting, much of which was 

 exceedingly profitable from the phycological point of view. Deep-water 

 dredgings were made mostly off the bow of the Velero by means of the 

 ship's dredge, while shallower areas were dredged by means of a motor 

 dredge launch. A glass-bottomed skiff was used for inshore raking, grap- 

 pling, and diving. The small dredge boat, being best suited for work over 

 the most excellent sublittoral vegetation areas, yielded the most interest- 

 ing sublittoral algal collections. Much of this material has never been 

 taken in any other way. 



The low tides of late January, 1940, made available some of the 

 richest shore stations under optimum collecting conditions. Later, during 

 February, in spite of relatively higher tides, the exceptional fall of ordi- 

 nary tides made all shore stations in the northern Gulf profitable. Brief 

 descriptions of the littoral and sublittoral stations together with accessory 

 data are to be found on pp. 353-356. 



In July, 1940, in order to study the seasonal change in the algal flora, 

 a return trip was made to Turner's Island, the only island station visited 

 in January by the Hancock Expedition which could be reached without 

 unreasonable difficulty. Turner's Island is 25 miles seaward from Kino 

 on the Sonora coast and may be reached by small boat owing to the safety 

 afforded by the shores of Tiburon Island which extend far out into the 

 Gulf. The trip was made in three days by outboard motor attached to a 

 one-ton fishing dory. We crossed the channel between Tiburon Island 

 and the mainland, followed the south shore, and then crossed to the reef 



