706 MR. R. H. BURNE ON MYXINK GLUTINOSA. [DeC. 20, 



Fig. 5. Transverse section through the clitellum of the same, to show the 

 unicellular layer of the epidermis and the hollow fibres of the ti-aiis- 

 rerse muscular coat. 



6. Ventral view of the genital segments ot Benhamia erassa; the clitellum 



is shaded and the groove connecting the atrial pores is shown. 



7. Spermatotbeca of the same. 



8. Calciferous glands of Microdri/us asiaticus. 



9. 10. Genital setje oi AcatitJwdri/iis smifM. in lateral and ventral view. 



11. A rudimentary calciferous gland of Eudriioides durhanensis. 



12. A spermatotbeca of Acanthodrilus smitlul. 



13. A penial seta of Jklicrodrilus asiaticus. 



14. Gemt&l OTgiLa&oiEv.driloides dvrhanensis; the segments are numbered. 



2. On the Presence of a Brancliial Basket in Myxine 

 glutinosa. By R. H. Burxe, B.A.^ F.Z.S., Anatomical 

 Assistant at the Royal College of Surgeons of England. 



[Beceived December 6, 1892.] 



(Plate XLYII.) 



One would expect the branchial basket, which forms such a large 

 and striking part of the skeleton of the Lampreys, to be present, at 

 least to some extent, in their nearest allies, the Hags ; and, in fact, 

 such is the case, for in 1835 Johannes Miiller, in his work upon the 

 Myxiuoids^ described and figured a small triradiate piece of cartilage 

 supporting the anterior and dorsal faces of the cutaneo -oesophageal 

 duct of Bdellostoma, which cartilageno doubt is the homologue oJ" 

 a branchial basket. Again, in 1883 Parker ■ mentioned this carti- 

 laginous support to the cutaneo-oesophageal duct of Bdellostoma, 

 representing it as an irregular plate having the same position as 

 Miiller's triradiate cartilage. 



Manifestly, as far as Bdellostoma is concerned, there is a branchial 

 skeleton which, although present on one side only, cannot well be 

 anything but a branchial basket in a very much reduced condition. 

 This being the case, one would naturally expect to find some such 

 supporting structure to the gill-tubes of Myxine glutinosa, but 

 neither Miiller, Parker, nor, as far as I can discover, any other 

 observer has found anything answering to it ; I fancy, however, that 

 Miiller implies in a passage which I quote below ' that he believed 

 that some such branchial skeleton was present, although he was 

 unable to actually demonstrate it. 



"While lately preparing a series of Marsipobranch skeletons for 

 the Museum cf the Royal College of Surgeons, I naturally was on 

 the look-out for this cartilage both in Bdellostoma and Myxine. 



' J. Miiller, ' Tergleichende Anatomic der Myxinoiden' (Berlin, 1835), p. 122. 



^ M". K. Parker, ■' On the Skeleton of the Marsipobranch Fishes. —Pt. I 

 Myxinoids," Phil. Trans. 1883. 



^ L. c. p. 122. " Dieaer Knorpel (in BdeHostoma) ist sehr zart und diinn, und 

 kann bei Myxine, wegen der Feinheit der Theile, nicht mehr nachgewiesen 

 werden," 



