59 
doppelt und weichen in ihrer Erscheinung nicht von den sonst be- 
schriebenen ab. 
Danach schließe ich mich denjenigen Autoren an, die glauben, 
daß die Centrosomen constante Bestandteile der Zellen bilden, glaube 
aber mit Hertwie (l. c.), daß sie in den meisten, vielleicht in allen 
Zellen während der Ruhe ihre Lage im Kern haben und sich deshalb 
nicht darstellen und erst bei Beginn der Teilung aus dem Kern in 
das Cytoplasma übertreten. 
Berlin, den 10. November 1892. 
Nachdruck verboten. 
Notes on Lampreys and Hags (Myxine). 
By J. Bearp, University of Edinburgh. 
(Author’s abstract of a short paper read before Section D (Biology) of 
the meeting of the British Association at Edinburgh, August 1892.) 
Two small specimens of Myxine glutinosa, 63 and 15 cen- 
timetres in length respectively were described. The smaller one had 
externally all the characters of the adult form. In transverse sections 
it was noted that the pronephros was functional, that the eye was 
as greatly degenerate as in the adult, that the nasal organ, which 
possessed the adult form, was of relatively large size, and that seg- 
mental mucous sacs were present. The most interesting point observed 
was that the young form possessed a dentition entirely different from 
that of the adult. The teeth were not confined to the floor of the 
oral chamber, as was the case with the exception of one tooth in the 
adult: there were several rows of well-marked teeth along the roof 
of the mouth. Indeed, from the dentition the animal might almost be 
described as gnathostomatous. In minute structure the teeth differed 
somewhat from those of the mature form, but a description of their 
structure was reserved. 
In the larger example (15 cm) the dentition alone had as yet 
been examined. The adult dentition was in course of development, 
and the “larval” teeth had disappeared. It was remarked that while 
the observations seemed to prove that in Myxine the Ammo- 
coete stage was not represented, it was obvious that a metamorphosis 
took place, as in the lamprey, and that this probably occurred when 
the animal was 14—15 cm in length. 
