22 ART. 12. K. YENDO. 



sufficient simply to remark that Corallina frondescens Post, et 

 RüPR. was referred to Arthrocardia by Areschoug,^^ though with 

 some doubt ; and that Arthrocardia was reduced to Ckeilosporum 

 by ScHMiTZ.^^ But I referred the Canadian algse to Cheilosporum 

 not merely because I was strengthened by Areschoug's opinion. 

 Some further remarks will be added below. 



The principal difference between this genus and Amphiroa 

 lies in the fact that in the former the mother cells of the propagat- 

 ing cells originate in the medullary portion of the fronds, while 

 in Amphiroa they are in the cortical. The scars of the dropped 

 conceptacles prove the difference. This is easily recognized by the 

 practiced eye. But to get the exact view, one microtome section 

 of the fertile articuli through a conceptacle is sufficient. This is 

 quite clear if the reader refers to the figures which I have re- 

 peatedly delineated in my former papers. ^^ 



The distinguisliing point between the typical forms of the 

 EucheilospoTum and the Alatocladia lies in the position of the 

 conceptacles. In the formei' the normal position of the con- 

 ceptacles is the upper margin of the sagittate articuli ; as a rule, 

 only one conceptacle is found in a wing of an articulus. In the 

 latter, one or more conceptacles are on the flat surface or the 

 outer margins of the wings of the reniform or sagittate articuli, 

 Hence the fertile branches of the Alatocladia have articuli with 

 a pair or more of conceptacles. Cf. PI. LVI. figg. 5, 7 and 18 

 in '' Cor. ver. Port Renfrew : " and PL II. figg. 12, 14 and IG 

 in " Cor. ver Japon." 



1) J. AG.: Spec. Alg. II. p. 549. 



2) Syst. Uebersicht. p. 455. 



3) Coral, ver. Japon. PI. II. figg. G, 8, 14 and 16: Cor. ver. Port. Renfrew. PI. LVI. 

 lîgg. ö and 8. 



