Algal Genera Acicularia and Acetabulum 333 



may be generally distinguished, but it seems to us that this de- 

 scription cannot well be applied to the plants of Kutzing. 



By way of further description of Kiitzing's specimens, it may be 

 remarked that the number of sporangia in a disc varies from 32 to 

 52, that the largest disc seen is 7 mm. in diameter, and that the 

 emarginate coronal processes bear two " hair-scars " or two unde- 

 veloped rudiments. The pocket in the Kutzing herbarium bears 

 the inscription, " Acetabidaria caraibica Lamx.," though why the 

 name should be attributed to Lamouroux is not quite clear. 

 Another specific name, with "Kg." after it, was first written, but 

 was so effectually scribbled out that we were unable to decipher it. 

 The pocket is numbered 103 and at the bottom is written <c Von 

 den Antillen. Koch." 



Explanation of folates 



Plate 24 



l-i6and 18-22. Acicularia Schenckii (Mob.) Solms. 



17. F rom Acetabulum crenulatum (Lamx.) Kuntze. 



1. Basal portion, showing rhizoidal food- reservoirs, X 28. 



2. Apical portion of a young plant, X l &* 



3. A later stage, showing beginnings of a primary whorl of sterile branches, X 55- 



4. Apex of plant crowned with well-developed primary whorl of sterile poly- 

 tomous branches, X 55- 



5- Apex of plant at a little later stage; primary branches falling and main axis 

 continuing its upward growth, X 55- 



6. Apical portion of plant, showing beginning of a disc, X 55- 



7. Three of the tooth-like processes constituting the young disc in Fig. 6, X 2 45* 

 outer (distal) aspect. 



8. Process from a slightly older cap-rudiment, distal aspect, X 2 45- At tne a P ex 

 {a) are seen the beginnings of what afterward will become the disc-filaments or the 

 abortive rudiments of such. 



9. The same a little more advanced, showing at b the first indication of the spor- 

 angium, X 245. 



10. A similar process viewed laterally, X 2 45- The beginning of the sporangium 

 at b. 



11. A primary process from a more advanced stage of the disc, in lateral view, 

 showing now at c the beginning of the hypopeltal process, X 2 45- 



12-15. Similar and later stages from various young discs, lateral views, X 2 45- 

 16. A primary disc-forming process at a little later stage than the preceding, in 

 distal view, X 245 ; b, the sporangium ; c, the hypopeltal process. The true apex, 

 with its two rudiments of disc-filaments, is hidden behind b. 



17- A primary di^c-forming process from Acetabulum crenulatum y showing rudi- 

 ments of three disc-filaments in a terminal whorl, X J 93- 



18. Young disc of Acicularia S henckii, seen from above (slightly flattened under 

 cover-slip), X 18. At this stage, with the present magnification, scarcely anything 

 more than the conspicuously pointed young sporangia is visible. 



