630 



wieder die innige Beziehung zwischen Nerv und Muskel erkennen und 

 zeigt, daß bei dem Auftreten anomaler Muskeln stets auch die Nerven 

 in Mitleidenschaft gezogen werden. Er zeigt uns aber auch zugleich, 

 daß solche abnorme oder accessorische Muskeln stets von denjenigen 

 Nerven versorgt werden , welche die Muskeln versorgen , von welchen 

 sie sich als selbständige Teile losgelöst haben. 



Note on the Blood -corpuscles of the Cyclostomata. 



By Professor d'Aecy W. Thompson in Dundee. 



It is commonly stated in the text-books, for example in Huxley's 

 ' Anatomy of the Vertebrata ', that the blood of the Cyclostomes differs 

 from that of all other fishes in the round instead of oval shape of 

 its red corpuscles. Gulliver, on whose authority most of the text- 

 book statements concerning the size and shape of blood - corpuscles 

 rests, says in his edition of Hewson's Works (p. 234): 'In the 

 Cyclostomes the corpuscles are of the same figure as those of 

 Man, and only slightly larger'. 



Accordingly I was more than a little surprised, on examining 

 some living Myxine lately, to find their red blood-corpuscles large 

 and oval, and similar to those of the Skate or Dogfish. On turning 

 up Johannes Müller's 'Vergleich. Anat. d. Myxinoiden', I found 

 that he had noted and figured the oval corpuscles of Myxine, but 

 without measuring them or calling attention to their points of contrast 

 with those of Petromyzon. Günther in his article 'Ichthyology' in 

 the Encyclopedia Britannica says accurately that 'the cor- 

 puscles of Petromyzon are round', but proceeds to say, that the 

 corpuscles of the Cyclostomes are exceptionally small, taking it for 

 granted doubtless that the two genera agree in this respect. 



I find the red corpuscles in Myxine to be thin flattened oval 

 plates, not bulging in the middle as in Mijller's figures, and with 

 a central nucleus which is sometimes round, more often elongated and 

 rod-like. Their dimensions are as follows: — 



Length . . . 0,025 to 0,028 mm 

 Breadth . . . about 0,01 mm 



Thickness . . „ 0,003 mm 



