A MONOGRAPH OF THE EXISTING CRESTOIDS 



229 



Gislen does not think that cirrus shape is sufficiently constant to provide useful 

 characters for distinguishing the species of Antedon but I disagree provided it is always 

 matui'e peripheral cirri which are described. 



Mr. A. H. Clark put forward no other character by which to distinguish between 

 bifida and moroccana and, judging from the variability in cirrus shape shown by bifida in 

 the table, this is of less than specific value. Nevertheless, the tendency for distal en- 

 largement of the ciiTi to occur in specimens from northwest Africa and the off-ly^ing 

 islands is sufficiently constant for the specimens from this area to be recognized as a 

 subspecies moroccana of A. bifida. 



Even apart from its doubtful distinction from bifida, the status of moroccana is 

 unsatisfactory. When named in 1914 it was distinguished only in a key, though brief 

 descriptions of specimens from Tangier, one of the several localities listed for it, had 

 been given in 1911 under the name of bifida. This was technically sufficient to es- 

 tablish it. The description given above was probably expanded from that of 1911 

 and so the three specimens from Tangier may be considered as syntj'pes, Tangier 

 being loosely included in Morocco. The specimens are in the Copenhagen Museum 

 and have more recently been renamed as Antedon dubenii by Dr. Gislen, together with 

 the specimens, which Mr. Clark had also included in moroccana, from Messina and 

 Ajaccio. 



Table 6. — Proportions of the cirrus segments in some specimens of Antedon bifida moroccana 

 {first five lots) and A. bifida bifida (below) 



See footnote at end of table. 



