25 



transmitted through a foramen in the massive cartilage. However in 

 Elasmobranchs it never pierces the Suspensorium. It always runs be- 

 hind the spiracle when the latter is present. 



The spiracle itself is not constant in relation to the hyomandi- 

 bular cartilage (or vice versa). In Polypterus, Acipenser and Spatu- 

 laria (van Wijhe) the spiracle is situated in front of the pterotic arti- 

 culation, which as I maintain, is at a fixed point relatively to the ear, 

 while in Heptanchus it is behind the same articulation. It is, of 

 course, also behind the spiracular cartilage of other Elasmobranchii. 



To make my meaning clear I may perhaps be allowed to ofier the 

 following modification of Huxley's diagram: 



Amphibia 

 Acipenser 



Teleostei Polypterus Ceratodus Eaiadae 



Cestracion 



Chimaera Notidanus Selachii 



Metautostylica Autostylica Amphistylica Hyostylica 



suspension from hyomandibular Z^" ". , , ■, 



'^ suspension from stylohyai. 



The Cyclostomi are as Huxley indirectly states "autostylic" and, 

 keeping in mind this fact, I wish in conclusion to protest as strongly 

 as possible against the term "visceral" or "branchial" arches being 

 applied to the cartilage elements of the jaws and hyoid apparatus. 

 Only those authors who suppose an absolutely unproved amount of 

 retrogression and modification in Cyclostomi can uphold this homology 

 and as has been maintained in my previous communication to this 

 journal these structures may have had an entirely ditferent origin, 

 namely, from oral cirri. 



Nachdruck verboten. 



Coloration de la my^line des tissus nerveux et de la graisse 

 par Tacide osmique et le tanin ou ses analogues. 



Par le Dr. Leok Azoxtlat, Paris. 



L'acide osmique en presence des solutions de noix de galle, de 

 tanin, d'acides gallique et pyrogallique, d'hydroquinone, d'iconogene 

 etc., donne une coloration fonc6e, bleu violet, ou brun noir, suivant 

 la quality et la quantite de ces derniers reactifs. 



