152 THE PLANTS 



sublittoral zone, and go down to depths even of 30 to 

 40 fathoms. The author has seen a bank of Litho- 

 thamnium dry at spring-tide, near the island of Timor, 

 but this is an exceptional case. It is a curious fact 

 that, however large a Lithothamnium bank may be, 

 it consists chiefly of only one species. Such banks 

 figure frequently on sea charts as " corals." 



The red algae are so numerous that it is difficult to 

 choose which deserve special mention. I will only 

 mention Constantinea rosa marina of Kamschatka (the 

 name implies its likeness to a flower), Rhodymenia 

 (Fig. 71), Ptilota, common in northern seas, Ceramium, 

 Polysiphonia (Fig. 70), Delesseria, Laurencia, plentiful 

 in temperate, but also found in tropical seas where 

 Claudea (Fig. 72) and Martensia occur by preference. 

 These examples could be multiplied endlessly ; per- 

 haps I have mentioned already too many. The kind 

 reader may be reminded of Harvey's Quaker, who 

 said : " Brother, if thou knewest what I keep in, thou 

 wouldst not grumble at what I let out." 



In 1899 there appeared from the hand of Professor 

 W. A. Setchell a paper containing directions for collect- 

 ing and preserving marine algae ("Erythea," vol. vii., 

 No. 3). Whatever the learned Professor advises the 

 collector to do, as to the best methods of collecting and 

 preserving algae, is the best that can be done. I can 

 only add a few details, and it is therefore with the kind 

 permission of Professor Setchell that I transcribe here 

 some passages out of his paper. For full information 

 on the subject I refer the reader to that paper. 



Collecting and Preserving Methods. — Wherever a 

 collector goes to seek for algae, he must first find out 

 the time of the tides from the local authorities. The 

 collecting-ground should be reached from one to three 

 hours before the occurrence of extreme low water, in 



