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BOTANICAL GAZETTE 



that up to a certain stage there is no recognizable difference between 

 the two ("auf diesem Stufe giebt es keinen erkennbaren Unter- 

 schied zwischen Fasergriibchen und Conceptaculum; wir haben 

 es mit der Erscheinung zu thun dass ein der Anlage nach identisches 

 Organ sich in einem Fall zu vegetativen, im anderen Fall zu repro- 

 ductiver Thatigkeit entwickelt"). 



The next important contribution to this subject was the paper 

 by Bower in 1880 (6), whose work has been generally accepted 

 since. In his introduction he gives a very brief resume of previous 

 work, given in the foregoing in greater detail. He first describes 

 the development of the conceptacle and then compares it with that 

 of the hairpit, which he regards "as an incomplete sexual con- 

 ceptacle" (p. 37). He agrees with Rostafinski (25) as to behavior 

 of segments of the apical cell, namely, that each segment divides 

 first by a wall parallel to its free surface; the outer cell again divides 

 in two planes at right angles to each other and to the first wall, 

 thus giving four cells which may repeat the same method of seg- 

 mentation as the original segment. A slight modification of this 

 behavior initiates a conceptacle (or hairpit). Upon completion 

 of a linear series of cells, activity in horizontal division ceases, 

 leaving the terminal (" initial") cell in a depression as surrounding 

 tissue continues active growth. This "initial" first loses its 

 internal tension and later shrinks back against the basal segment 

 beneath. Later segments of this basal portion (cortical in origin) 

 line the bottom of the cavity, whereas the sides are derived from 

 the limiting tissue (external layer) and from subjacent cortical 

 tissue. This is the method for Fucus. 



In Himanthalia (pp. 46, 48), the lining of the cavity is derived 

 entirely from limiting tissue. In Halidrys he finds (p. 45) tnat 



"The basal cell divides at first by walls strongly inclined to one another. 

 The cells thus produced do not at any early stage divide by walls parallel to 

 the surface of the cavity. The result is that the conceptacle usually appears 

 .... as though lined by a layer of cells continuous with the limiting layer; 

 but as part, at least, of this tissue is derived from the basal cell, this con- 

 clusion is inadmissible. Meanwhile the initial cell (or group of cells) has been 

 completely thrown off by the swelling of the wall dividing it from the basal cell. 



