CHONDRUS. 435 



examined in a fresh condition. The student should, 

 furthermore, make drawings of the sections before they 

 are permanently mounted. A permanent preparation of 

 an alga is often a very poor guide to the condition of 

 things obtaining in the living plant. A good drawing, or 

 even a careful sketch of a fresh section is at a later date 

 generally a far better reminder of what was seen in the 

 living plant than an old glycerine preparation. 



It is a useful plan to make the drawings on loose sheets, 

 and insert them in the herbarium with the dried specimens. 

 It is, of course, necessary to carefully label all slides at 

 once. This prevents any possible confusion to which a 

 later labelling by memory nearly always leads. 



II.— CHONDRUS CRISPUS (L.) Stackh. 



The species Chondrus crispus has now been definitely 

 recognised from the introductory description given in the 

 preceding part of this memoir. We can therefore proceed 

 to the more detailed description of the plant. 



A. — The External Morphology of the 

 Vegetative Organs. 



The plant body of Chondrus crispus shows a very dis- 

 tinct morphological differentiation into two parts — ' 

 namely, into a shoot and a root. Nevertheless it is 

 generally referred to as being a but little differentiated 

 thallus, the differentiation not being of quite the same 

 degree and kind which we meet with in the higher plants. 

 But it is possible to distinguish very clearly a root from 

 a shoot. The latter alone bears the reproductive organs. 



The Root is mainly an organ of attachment. In this 

 respect our alga resembles most of the higher aquatic 



