On Regeneration in Ctenophores. 
By 
Dr. Th. Mortensen. 
It has hitherto been generally accepted that the Ctenophores 
do not possess regenerating power. In his memoir on the Disso- 
gony”) Chun states (p. 103) that "den Ctenophoren nach den 
Ubereinstimmenden Berichten aller Beobachter ein Regenerations- 
vermågen abgetrennter Theile durchaus abgeht.”. Quite recently 
A. G. Mayer in his paper on the "Ctenophores of the Atlantic 
Coast of North America”?) (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?) I have called attention to the 
fact that there are really found some statements in litterature that 
the Ctenophores possess power of regeneration, viz. in Mertens' 
old workt) and in Chun's own celebrated memoir on the Disso- 
8ony. 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 half-embryos, produced by separating the 
two first cleavage cells, ultimately regenerate the lacking half part 
of the body. — In view of such fact it would, indeed, be very 
7) C. Chun: Die Dissogonie, eine neue Form der geschlechtlichen 
Zeugung. Festschrift f. Leuckart 1892. 
?”) Publ. Carnegie Inst. of Washington 162. 1912. 
”) Th. Mortensen. The Danish Ingolf Expedition. Vol. V. 2. 1912. p. 81. 
") H, Mertens. Beobachtungen und Untersuchungen iiber die Beroe- 
artigen Akalephen. Mém. Acad. d. Sci, St. Pétersbourg. 6 Ser, II. 1833. 
