318 ORIGINAL ARTICLES. 



branchial arch, whose epibrancliial segment (Owen) is expanded into 

 a broad triangular plate ; the accessory organ lies upon this plate in 

 such a manner, that the axis of its spiral canal keeps a perpendicular 

 direction throughout. 



The right and left organs communicate by a common aperture 

 with the roof of the pharynx, immediately behind the toothed pha- 

 ryngo-branchial segments (Owen, pharyngiens superieurs Cuv.) The 

 lining membrane of these organs is very vascular, and fine injection 

 proved beyond contradiction, that their arteries are but prolonga- 

 tions of those which bring the venous blood to the gills. Their veins 

 unite with the root of the aorta, and must, therefore, contain arterial- 

 ised blood. On the inner border of the twisted tube there is a 

 double row of fringes, of the consistency of cartilage, and a groove 

 lies between the two rows, but there is no interspace* like a branchial 

 cleft. 



Our great anatomist Johannes Muller, threw out a hint of the 

 existence of this organ in his admirable work " Bau und Grenzen der 

 Ganoiden," p. 74 et seq. ; but the specimen which he had for dissec- 

 tion was probably so defective as to cause him entirely to overlook 

 its peculiar snail-like convolution, and he only speaks of the above 

 mentioned double series of fringes, which he declared to be a true 

 biserial gill. Careful investigation of well injected preparations, has, 

 however, satisfactorily convinced me, that the biserial gill of Muller 

 is not a respiratory gill, but simply a continuation of the peculiar 

 horny fringes, which are attached to the concave border of the bran- 

 chial arches in many Clupeid and Scomberoid fish, and which serve 

 as combs, or gratings, to intercept any solid particle swallowed, which 

 if forced through the interspaces of the branchial arches would, most 

 certainly, injure the very delicate vascular net-work, supported by the 

 slender and compressed processes of the gill fringes. 



A very large branch of the pneumogastric nerve supplies the 

 inner side of this organ (to which I give the name of Cochlea 

 branchialis), and it strikes me that its mucous membrane may be 

 capable of receiving some special sensation. The organ is surrounded 

 by a strongly developed muscular coat, so that the water contained 

 in it can, by the contraction of the muscles, be easily expelled 

 through the same orifice by which, on dilatation, it enters. 



On a former occasionf I have pointed out that some of the true 

 clupeid fish, as Meletta, Chatoessus, Chipanodon, Gonostoma, &c 



* In a note Prof. Hyrtl says — The branchial clefts are very long and narrow 

 in all clupeid fish, and the fringes on the convex border of the branchial arches 

 are of so delicate an organization and possess such an extremely fine capillary net- 

 work, that all the clupeid fish die the instant they are taken out of the water. 

 Prof. Hyrtl suggests that hence the origin of " As dead as a herring." 



[The only objection to this explanation which occurs to us is that, as all who 

 have seen herrings caught, know very well, the fish do not die the instant they come 

 out of the water ; nor indeed sooner than many other fisb. — Eds.] 



t Denkscbriften der K. K. Akademie der Wissenschaften, Wien. lOBd.pag. 47, 

 " Ueber die acccssorischen Kicmenorgane der Clupeaceen." 



