no. 1808. RECENT AFRICAN CRINOIDS— CLARK. 39 



Asterias bifida Pennant, British Zoology, vol. 4, 1777, No. 70. 



Antedon rosacea P. H. Carpenter, Zool. Anzeiger, Jahrg. 4, 1881, p. 521; Chal- 

 lenger Reports, vol. 26, Zoology, 1888, pp. 355, 377.— J. Barrois, Rev. 

 biol. du nord de la France, vol. 1, 1889, pp. 32, 33. 



Antedon bifida Bell, Ann. and Mag. Nat. Hist., (6) vol. 4, 1889, p. 432. 



Locality. — Azores (common); Bay of San Pedro (abundant); 

 Algiers; Tangier; Morocco; Madeira. 



Remarks. — There are three specimens of this species in the Copen- 

 hagen Museum collection which were collected at Tangier; one of 

 them has the arms about 60 mm. long, rather stout, and cirri XXXV, 

 13-15 (usually 15) about 12 mm. long; Pj is 12 mm. long with 

 twenty-five segments, and P 2 5 mm. long with sixteen segments; 

 the production of the distal ends of the segments of the proximal 

 pinnules is marked; another is similar, with arms 60 mm. long and 

 cirri XXX, 14-16; it has eleven arms, one of the IBr axillaries (the 

 right posterior) bearing on the right (i. e., anterior) side a single 

 axillary; the third specimen is similar to these, but smaller, with 

 amis only 40 mm. long. 



In general structure and in the details of the arms, especially the arm 

 bases and the IBr series, these animals appear to be identical with a 

 series at hand from southern England and the Channel Islands; 

 moreover, there are the same small clusters of perisomic interradials 

 in each interradial angle. A specimen from Plymouth, England, so 

 far as I can see, matches them exactly in all respects. 



It was somewhat of a surprise to me to find this species at Tangier, 

 south of the Straits of Gibraltar, instead of the quite different A. 

 mediterranea. It is more surprising still to find an example with 

 eleven arms showing a physiological similarity as well as a similarity 

 in form between specimens from England and from Africa; for of 

 the four species of Antedon, A. bifida is the only one which, so far as 

 known, ever exhibits any tendency toward an increase in the number 

 of the arms over the primitive ten. 



But the most curious fact of all is that it is this species and not 

 A. mediterranea which occurs at Algiers. I have recently examined 

 five specimens and several pentacrinoids from that locality which 

 are in the Paris Museum. They resemble closely those from Tangier 

 just described, but the cirri are XXIV-XXX, 12-14 (usually 13-14). 



Carpenter has recorded "Antedon rosacea" from Madeira. While 

 his specimens probably are of the present species, there is a possi- 

 bility that they are in reality Antedon hupferi. 



ANTEDON MEDITERRANEA (Lamarck). 



dsKUKvejiog crocea Linck, De stellis marinis, 1733, p. 53 (based upon the 



dznadaouanTcvoecdyg of Columna, 1592). 

 JeKOKusfioc barbata Linck, De stellis marinis, 1733, p. 55, pi. 37, fig. 64 (based 



upon the JeKaKvenoffimbriata of Barrelier, 1714). 



