526 BULLETIN 82, UNITED STATES NATIONAL. MUSEUM. 



aperture on the fascial side of each conceptaeulum, still, however, adhering together in a 

 roundish cluster of about 100 each, by means of the extension and connection of their umbilical 

 cords. By what means these ova are dispersed, or how they become attached to the stems and 

 branches of corallines, remain to be discovered ; but it is strongly to be suspected that the 

 animal Is gifted with the power of placing them in appropriate situations; otherwise we 

 should find them indiscriminately on fuel, shells, stones, etc., which does not appear to be the 

 case. 



He also remarked that the great abundance of comatulids in the places they 

 inhabit is not to be wondered at when we are aware how exceedingly prolific they 

 are; thus each arm may be estimated to bear 30 fruitful conceptacles, each pro- 

 ducing about 100 ova, and, as there are 10 such, this gives 30,000 as the amount 

 of ova produced by a single individual. 



According to J. V. Thompson and Sir Wyville Thomson, the casting off of 

 the stalk takes place not before the middle of August and usually not later than 

 the middle of September. Since Sir Wyville determined the maturity of the eggs 

 as occurring at the end of May or the beginning of June, the duration of the 

 stalked life is from two and a half to four months. 



W. B. Carpenter states that the larvae detach themselves from the stalk 

 after a developmental period of from five to six months. When detached they 

 are far from mature, acquiring maturity at the earliest in the following summer. 

 He says that the full-sized animals are probably several years old. 



Sir Wyville Thomson noticed that the larvae sometimes remain free swimming 

 for many days, and Busch kept larvae for a considerable time without their 

 becoming attached. 



ANTEDON MOROCCANA. 



Though the pentacrinoids of this species have been studied in great detail 

 by Perrier, as he did not distinguish between this form and Antedon bifida and 

 A. mediterranca it is impossible to say to which of the three his remarks apply. 

 I saw many of these pentacrinoids from Algiers in the Paris Museum, but I had 

 no time to study them in detail. 



Perrier writes that the larvae of the comatulids live during the greater part 

 of their development either adhering to the pinnules of the mother or fixed to 

 submerged bodies, such as algae, bryozoans, hydroids, the tubes of annelids, etc. 

 This may refer in part to the young of A. moroccana, since the young of none 

 of the other species of Antedon have as yet been found upon the parent. 



ANTEDON MEDITERRANEA. 

 Figs. 1337-1340, pi. 51. 



Chadwick's account (1907) of the development of Antedon bifida and his 

 figures are based upon this species, his material having come from Naples. 



The pentacrinoids of Antedon mediterranea agree in almost all particulars 

 with those of Antedon bifida, but they appear to be slightly less robust, with 

 slightly longer columnals. 



There are usually three infrabasals. 



The columnals number 13-15. 



