28 INTRODUCTION. IV 



stems of mangroves near high water mark ; but it would extend this notice 

 to too great a length, were I to enumerate all the forms which occur in this 

 prolific region. 



COLLECTING AND PRESERVING SPECIMENS. 



I shall here reprint, for the convenience of the student, the substance of some 

 directions for collecting and preserving specimens, issued by the Director of the 

 Dublin University Museum. 



Marine Algae, as has already been stated, are found from the extreme of high 

 water mark to the depth of from thirty to fifty fathoms ; which latter depth is 

 perhaps the limit in temperate latitudes ; the majority oi deep water species growing 

 at five to ten fathoms. Those within the limits of the tidal influence are to be 

 sought at low water, especially the lowest water of spring tides ; for many of the 

 rarer and more interesting kinds are found only at the verge of low water mark, 

 either along the margin of rocks partially laid bare, or, more frequently, fringing 

 the deep tide-pools left at low water on a flattish rocky shore. The northern or 

 shaded face of the tide-pool will be found richest in red algte, and the most sunny 

 side in those of an olive or green colour. Algse which grow at a depth greater than 

 the tide exposes, are to be sought either by dredging ; or by dragging after a boat 

 an iron cross armed with hooks, on all shores where those contrivances can be 

 applied ; but where the nature of the bottom, or the difficulty of procuring boats, 

 renders dredging impossible, the collector must seek for deep-water species among 

 the heaps of sea-wrack thrown up by the waves. After storms seaweed sometimes 

 forms enormous banks along the coast ; but even in ordinary tides many delicate 

 species, dislodged by the waves, float ashore, and may be picked up on the beach in 

 a perfect state. The rocky portions of a coast should, therefore, be inspected at 

 low water ; and the sandy or shingly beach visited on the return of the tide. In 

 selecting from heaps we should take those specimens only that have suflbred least 

 in colour or texture by exposure to the air ; rejecting all bleached or half melted 

 pieces. 



Collectors should carry with them one or two strong glass bottles with wide 

 mouths, or a handbasket lined with japanned tin or gutta percha, for the purpose 

 of bringing home in sea ivater the smaller and more delicate kinds. This precaution 

 is often absolutely necessary, for many of the red algaj rapidly decompose if 

 exposed, even for a short time, to the air, or if allowed to become massed together 

 with plants of coarser texture. The cooler such delicate species are kept the better ; 

 and too many ought not to be crowded together in the same bottle, as crowding 

 encourages decomposition ; and when this has begun, it spreads with fearful rapidity. 

 These Alg« should be kept in sea water until they can be arranged for drying, and 

 the more rapidly they are prepared the better. Many will not keep, even in vessels 

 of sea water, from one day to another. 



A common botanist's-vasculum, or an Indian rubber cloth bag, will serve to 

 bring home the larger and less membranous or gelatinous kinds ; but even these, if 

 left long unsorted, become clotted together, and suffer proportionably. 



