On Regeneration in Ctenopkores. 
By 
Dr. Th. Mortensen, 
It has hitherto been generally accepted that the Ctenophores 
do not possess regenerating power. In his raemoir on the Disso- 
gony 1 ) Chun states (p. 103) that “den Ctenophoren nach den 
iibereinstimmenden Berichten aller Beobachter ein Regenerations- 
vermogen abgetrennter Theile durchaus abgeht.”. Quite recently 
A. G. May er in his paper on the “Ctenophores of the Atlantic 
Coast of North America” 2 ) (p. 52) says that “probably every one 
who has studied living Ctenophores will agree that, while their 
healing power is remarkable, they appear to have little power to 
regenerate lost parts.” 
In the “Ingolf’-Ctenophora 3 ) I have called attention to the 
faet that there are really found some statements in litterature that 
the Ctenophores possess power of regeneration, viz. in Hertens’ 
old work 4 ) and in C hun’s own celebrated memoir on the Disso- 
gony. While the observations of Mertens are, at least in part, 
doubtful, those of Chun are sure enough, and, indeed, most in- 
teresting — viz. that the lialf-embryos, produced by separating the 
two first cleavage cells, ultimately regenerate the lacking half part 
of the body. — In view of such faet it would, indeed, be very 
*) C. Chun: Die Dissogonie, eine neue Form der geschlechtlichen 
Zeugung. Festschrift f. Leuckart 1892. 
2 ) Publ. Carnegie Inst. of Washington 162. 1912. 
3 ) Th. Mortensen. The Danish Ingolf Expedition. Vol. V. 2. 1912. p. 81. 
4 ) H. Mertens. Beobachtungen und Untersuchungen liber die Beroe- 
artigen Akalephen. Mém. Acad. d. Sci. St. Pétersbourg. 6 Ser. II. 1838. 
