708 MR. R. U. BURNE ON MYXINE GLXJTINOSA. [DeC. 20. 



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

 skeleton to the true gill-tubes on hofh 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 Bdellostotna , 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 Mxjxine, 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 suggestions, he has allowed me to profit by 

 his experience. 



EXPLANATION OP PLATE XLVII. 

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



(X n.) 



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. 



(X -U.) 



4. Right half of the branchial basket of Myxine glutinosa isolated. 



(X2i) 



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



rhatum. (Nat. size.) 



6. ^rsmchisA hasiet oi Bdellostoma cirrhatmn. (Nat. size.) 



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

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

 the left side. C. Branchial basket of the right side. C.ceD. Cutaneo- 

 oesophageal duct. G'-G". Gills. <£. CEsophagus. T. Tongue. 



