4 Vol. XLIII., Art. 1.— K. Yendo: 



wanting in others. They are different from those found in Fuca- 

 ceao, in structure and in mode of formation. 



The characteristic of the genus is the formation of the sporo- 

 phylls, as the generic name Alaria suitably expresses. Tlie sporo- 

 phylls are small leaflets, each provided with a short but more or 

 less sharply differentiated petiole at its base. They are disposed 

 pinnately or fasciculately on both edges of the terete or com- 

 pressed stipe. 



In minor points, the characters of the frond vary according 

 to the species ; or it is better to say, the specific distinctions of 

 Alaria lie on the minor differences of the characters. It is there- 

 fore a most important matter to ascertain if a character is con- 

 stant or variable, and consequently, reliable or unreliable for specific 

 distinctions. The observations given below will help to solve the 

 problem, and at the same time explain the standpoint on which 

 the present waiter has arranged the species. 



The stipe of the embryonal frond of Alaria is cylindrical. Its 

 greater part of thickness consists of septated filaments running 

 parallel and compactly arranged. The part is enveloped with a 

 few layers of rectangular cells containing chromoplasts. Later on, 

 it adds to its length by stipo-frondal growth, until the frond 

 reaches the post -embryonal stage. The upper half of the length 

 of the stipe at this stage is moi'o or less compressed with round 

 edges, generally becoming cylindi-ical downwards. The structure 

 is now înore complicated than in the embryonal stage, and does 

 not show much difference in its essential points from that of the 

 other Laminariaceous members. The tissue elements may be briefly 



