OLIVE-BROWN SEAWEEDS. 243 



The constants of the case are these. The Fucacece 

 have their reproductive organs buried in more or less 

 round, flask-shaped pits beneath the surface called con- 

 ceptacles, where they occur among- hairs — paraphyses. 

 Often on the same species there occur pits of precisely 

 the same mode of development which contain the hairs, 

 but no reproductive organs. These barren pits are what 

 have been termed the sterile or neutral conceptacles, Faser- 

 griibchen, cryptostomata, etc. The development of these 

 conceptacles was first accurately investigated by Professor 

 Bower (1). His observations were greatly extended by 

 Oltmanns (2), who described their occurrence in many 

 other genera of Fucacece. Miss Barton (3) added to this, 

 and discussed the subject further (4) in its later develop- 

 ments. In their investigation of the remarkable type 

 Splachnidium, for which they founded a new natural order, 

 Miss Mitchell and Miss Whitting (5) discovered a new kind 

 of conceptacular body, developing after a fashion of its own, 

 and containing not oogonia and antheridia like those of 

 Fucacece., but sporangia like those oi Laminar iacece. It is 

 a different kind of conceptacle, but yet clearly comparable 

 with that of Fucacece. The present writer (7) next investi- 

 gated the barren cryptostomata of three Laminarian genera, 

 and found them different from but comparable with those 

 of Splachuidiacece. The interesting point now comes in, 

 though of course it has been known for a long time, that 

 the Laminarian cryptostomata are always barren, and that 

 the ordinary occurrence of "sporangia in this order is in 

 patches or sori where they are mixed with paraphyses, 

 quite apart ordinarily from any cryptostomata. In one of 

 the genera, however (Adenocystis), these pits occur right 

 in the middle of the sori, but are themselves barren. About 

 the same time and working in the same laboratory Miss 

 Mitchell (6) found a simple form of pit or cryptostoma in 

 another order (Fncceliaccce) in the genus Hydroclathrus, 

 also in the middle of sori this time of plurilocular sporangia. 

 Miss Barton has noted the occurrence of other pits of the 

 kind on the barren thallus of Chnoospora (Sporochnacece ?) 

 and they have been long known as very shallow pits on 



