THE ELK-KELP. 181 



In each case the holdfast was still attached to a small 

 stone, and was about the size of a man's two fists. The 

 small size of the holdfast, in this case, is in great contrast to 

 that of Macrocystis which is often a meter across. The hap- 

 teres are produced in several, fairly regular whorls, at the 

 base of the stipe and are several times regularly dichot- 

 omously branched, the ultimate brauchlets being very slender 

 and somewhat fasciculate. 



The stipe is solid at the base, perfectly terete and very 

 slender. It increases very gradually and very slightly in 

 diameter for about 6.7 meters in each specimen. Then it 

 becomes abruptly swollen for a distance of about 80 centi- 

 meters and is hollow within. This swollen, hollow portion 

 is more or less abruptly and distinctly marked off from the 

 lower solid portion, and very sharply separated from the 

 bladder above by a deep constriction. The upper swollen 

 portion of the stipe in JSf. Luetkeana is also distinctly 

 marked off from the bladder and from the lower part of the 

 stipe, although not so distinctly as in N. giganiea. It will 

 be very convenient to designate this swollen portion in both 

 species as the apophysis. 



The bladder is nearly spherical, 18 to 20 cm. in diameter, 

 and is separated from the apophysis by a deep constriction, 

 much more pronounced than that of iV. Luetkeana. In the 

 latter species, indeed, there is frequently no constriction at 

 all. The cavity of the bladder communicates with that of 

 the apophysis by a narrow canal, 3 to 5 cm. in length and of 

 the diameter of a goose-quill. The connecting cavities of 

 bladder and apophysis, both in N. giganiea and in N. Lu- 

 etkeana, are ^Wed with a gas of some sort, so long as the 

 plant is alive and uninjured. A number of specimens of 

 both species were examined carefully to test this point and 

 in no instance Avas any water found inside, except in the 

 case of injured specimens. In specimens thrown ashore, 

 considerable water is often found inside, but there is always 

 present either a hole through the wall, or else a spot where 

 the tissues of the Avail are soft and dead. The writer was led 



