A REVISED LIST OF CORALLINiE. 11 



superficial position of the conceptacles ; and from the latter by 

 the cortical origin of the mother cells of the spores. 



I am no less in doubt in classifying Aynp. cretacea Endl. in 

 the same section with Amp. decUnata. The position of the con- 

 ceptacles is very irregular in the former species, while in the latter 

 the conceptacles are arranged in a definite regularity. Amp. cre- 

 tacea and its forms are widely distributed in the colder seas of 

 both the northern and the southern hemispheres. It may claim 

 an independent position. The above disposition is a provisional 

 one until we find a more special character in Aiiip. cretacea. 



Amp. breviarticidata Aeesch. and Amp. capejisis Aresch. 

 seem to be nearly allied to Amp), cretacea Endl. According to 

 the descriptions given by Areschoug^^ we can hardly distinguish 

 the former from var. tasmanica Kutz. This has been already 

 noted by Sonder."^ Amp. capensis Aresch. is also unseparable 

 from Amp. cretacea., except that the basal genicula are compara- 

 tively longer. Amp. dubia Kütz., judging from the figures of 

 Tab. Phyc. VIII. Tab. 49. fig. 1., is referrible to Amp. capensis 

 Aresch. These species have hitherto been distinguished by the 

 relative size and forms of the articuli ; but these points can hardly 

 be relied upon to warrant a specific character. 



Madam Weber doubts Amp. hreviarticulata Aresch. She 

 found an Artkrocadia called by that name in Suringar's her- 

 barium, and tried in vain to see the type of Areschoug's species. 

 Judging from the original descriptions, I believe the specimen 

 found by her is different from what AreschouG meant. 



Amp. cretacea has been defined as often having recurved or 

 flexuous articuli. Areschoug put too much stress on this character 



1) Spec. Alg. IT. p. 532. 



2) Linnea. XXV. p. 687. 



