62 Adenocystis, Alaria and Saccorhiza. 



specially noteworthy. His description of the old cryptostomata, of which he 

 does not give a figure, as saucer or shallow bowl-shaped depressions, with 

 a large number of hairs projecting from the bottom, and with a rim pro- 

 jecting in over the edge of the depression, is sufficiently like my figure of 

 those of 5. bulbosa (plate XVI., fig. 7). 



It appears to me to be a very probable explanation of the arrested 

 development of the cryptostomata in Alaria (if I may put it in that way) 

 that the frond of Alaria remains thin and easily lacerated so thin as to 

 give no room for the development of pits on either side and I am 

 confirmed in this view by Mr. Setchell's observation (loc. tit.} that ' the 

 cryptostomata are present on the one layered portion of the blade (of 

 Saccorhiza dermatodca] as clusters of hairs upon the flat surface.' 



Kjellman,* in his paper on the forms of Adenocystis, has figured the 

 cryptostoma of A. Lessonii Hook, et Harv. Mr. R. M. Laingf has also 

 figured this body, and mentions and illustrates ' oval sacs containing 

 zoogonidia' in the cryptostoma of Adenocystis. These sacs do not appear 

 to belong to the species of Streblonema, which commonly invests the 

 cryptostomata of this plant, and their presence may or may not be 

 accidental. This plant has so many points of structure in common with 

 Splachnidium that an occurrence of such sporangia would possess a par- 

 ticular interest. On examining the original material of Adenocystis 

 collected during the Antarctic voyage, and also some New Zealand 

 specimens, kindly lent me by Mr. Harvey Gibson, I was not satisfied with 

 the accuracy of either Kjellman's or Laing's figures, and have therefore 

 given another rendering of this structure (plate XVI., fig. 2), from which it 

 will be seen that it bears a resemblance, both to the cryptostoma of its 

 ally, Saccorhiza, and to those of Hydroclathrus (plate XIV.), illustrated 

 by Miss Mitchell. Though I have examined a very young plant, I was 

 unable to secure sufficiently early stages to ascertain the development of 

 the cryptostoma. The result, however, is sufficiently remarkable. These 

 cryptostomata occur in the middle of sori of nniloatlar sporangia, and the 

 paraphyses and sporangia will be seen in the figure (plate XVI., fig. 2) on 

 the very border of the depression. The sporangia and paraphyses are truly 

 Laminarian, as would be expected. In the other Laininaricc examined, 

 the sorus occurs separately from the cryptostomata, but, in this form, in the 

 middle of the sporangia and paraphyses, as if in a nascent effort (or a 

 dying one, as the case may be), to form a conceptacle like that of Splac/t- 

 nidimn. It will be remembered that a young conceptacle of Splachnidium 

 bears hairs only at first and sporangia later on. 



* Bihang till K. Svenska Vet. Akad. Handlingar, bd. xv., afd. Hi., No. I. 

 t Trans. New Zealand Institute, vol. xviii., p. 306, plate X., fig ?. 



