PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 125 



southern one, hupferi, from Sierra Leone round into the Gulf of Guinea, with cirri more 

 like those of A. petasus. I had not specidated on their relationship with duebeni beyond 

 commenting that, from the data available, the latter seems to have cirri of the expanded 

 moroccana-type. 



Gislen believed that the shape of the profile of the cirri is too variable in any one 

 specimen to be used as a specific character and gave photographs of cirri from speci- 

 mens of petasus, bifida, and two from West Africa which he called diibenii, in support 

 of this. There is indeed some variation in the shapes of the individual cirri of each 

 specimen, but it is clear that the form depends on the maturity of the cirrus. The 

 younger, more apical (or possibly regenerated) ones are consistently less expanded 

 distally than the mature, peripheral ones and in Gislen's figures 1 (petasus) and 4 

 (which I should call hupferi) there is obviously a paedomorphic tendency with the 

 peripheral cirri retaining to some extent their juvenile form, unUke those of his figures 2 

 (bifida) and 3 (which I should call bifida moroccana). In fact I think that Gislen's 

 figures only support my contention that two distinct species exist off West Africa. 



[1961. I have recently been able to examine some of the Atlantide specimens in 

 the Zoological Museimi, Copenhagen. Most of them fall into two groups: those with 

 relatively narrow cirri (hupferi) from stations south and east of Liberia and those with 

 distally widened cirri from stations to the west and north (moroccana), but I must 

 admit that some specimens are intermediate in this respect. However, when there 

 are several specimens from a single station, they all have cirri of similar shape and the 

 range of variation in any one area is clearly hmited.] 



In an attempt to clarify the position of moroccana with regard to bifida, I measured 

 the median widths of the fourth segments from the base and the fourth from the tip 

 of mature peripheral cirri of a nimiber of specimens of Antedon. Of these, 10 from the 

 Azores, 3 from Goree, just south of Cape Verde (named hupferi by Mr. A. H. Clark 

 in 1911 before he distinguished moroccana) , and 2 from Algiers very kindly sent by 

 Prof. Tortonese at my request, I believe are referable to moroccana. Other specimens 

 measured were a number of bifida from various parts of the British Isles and 8 which 

 I beUeve represent hupferi, from off Sierra Leone and Ghana. The details of these are 

 given in tables 3 and 6 on pp. 155 and 229-230 but, to sum up, the ratio of distal to 

 proximal width varied in the 15 specimens of moroccana from 1.33 to 1.80:1, averaging 

 1.57:1 (though only the two from Algiers and one of those from Goree, all of which are 

 relatively small, have the value less than 1.5 :1). In 40 specimens of bifida the range was 

 from 1.09 to 1.67:1, averaging 1.43:1. The specimens of bifida with values over 1.5:1 

 were all associated with others in which the ratio is lower, there being no marked 

 tendency in bifida from any one locality to show a consistently high level. As for 

 hupferi, the range was from 1.25 to 1.50:1, averaging 1.36:1, and in none of the speci- 

 mens was the distal enlargement of the cirri so marked as in the adult specimens of 

 m,oroccana. The cirri shown in Gislen's figure 4 of a specimen (which he called diibenii) 

 from off Nigeria agree with those of the specimens I have called hupferi, while those 

 in his figm-e 3, from one taken off Portuguese Guinea, north of Sierra Leone, agree 

 with moroccana. I think his decision to synonymize moroccana (and hupferi) with 

 the west Atlantic duebeni is premature in view of the very scanty material of the 

 latter known at present. 



It is unfortunate that Gislen gave no details of the proportions of the cirri in his 

 various West African specimens since he discounted this character. Despite his greater 



