708 MR. R. H. BURNE ON MYXINE GLTJTINOSA. [DeC. 20. 



the support to the cutaneo-cesophageal duct, there is also present a 

 skeleton to the true gill-tubes on hoth sides, thus to a certain very 

 slight extent bridging over the gap between the small unpaired 

 basket of Bdellostoma on the one hand and the enormous com- 

 plex branchial basket of the Lamprey on the other. It is worthy of 

 note that in Bdellostoma, a creature which approaches the Lamprey 

 very nearly in the structure and general form of its gills, the gill- 

 skeleton is reduced to a minimum, whereas Myccine, with its highly 

 specialized gills, in its gill-skeleton inclines towards the perfection of 

 the Lamprey. 



In conclusion I wish to thank Professor Stewart for the kind way 

 in which, by criticism and suggesti ons, he has allowed me to profit by 

 his experience. 



EXPLANATION OF PLATE XLVII. 



Fig. 1. Myxine qlutinosa dissected from the left, showing gills and gill-skeleton 

 (X 2f.) 



2. Myxine glutinosa dissected from the right, showing gills and gill- 



skeleton. ( X 2|.) 



3. Left half of the branchial basket of Myxine glutinosa isolated. 



(X2i.) 



4. Eight half of the branchial basket of Myxine qlutinosa isolated. 



(X2|.) 



5. Cutaneo-oesophageal duet and branchial basket of Bdellostoma cir- 



rhatum. (Nat. size.) 



6. Branchial basket oi Bdellostoma cirrhatum. (Nat. size.) 



Bejerence letters : — A. Cutaneo-oesophageal branchial basket. B. The por- 

 tion of the branchial basket in Myxine which sujjports the true gill-tubes on 

 the left side. 0. Branchial basket of the right side. O.oeD. Cutaneo- 

 oesophageal duct. G^-G^. Gills, oe. OEsophagus. T. Tongue. 



