Videnskabelige meddelelser

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Videnskabelige meddelelser

293

s'unit å ses deux voisines par des petites lamelles transversales

jusque pres de son extrémité en sorte que la surface de la branchie

ressemble plutot å un réseau qu'å un peigne."

If examined closely the gill will, in spite of the modifications,

show all the primitive features. Each lamella has its sceleton-rod,

afferent and efferent vessels, respiratory plaits etc. The Strange

aspect of the gill is effected by the faet that the branchial lamellae

in the same row are connected with each other in several piaces

p

Fig. 1. Xiphias. Transversal section of a row of branchial lamellae,

X 12. Pores p, and connecting bi-idges, c are to be seen. A sceleton

of lamella. O ossiticatlons from the ouler and O. from the inner surface

of hemibraneh (decalcinated). Semidiagrammatic.

so that the water can only get into contact with the respiratory

epithelium through numerous, serial pores. These pores are cir-

cular on the inner surface of the hemibraneh but oblong on the

outer (Plate XVIII). The connections are most solid on the inner

surface of the hemibraneh. Here the connecting bridges are sup-

ported by cartilaginous protuberances from the sceleton of the

lamella. These protuberances are in contact with each other, but

they are not confluent ; a line may be seen marking the limit be-

tween each pair (se textfigure).

Another striking feature in the structure of the gill is the

layer of ossifications, which is found on both surfaces of the hemibraneh.

This has been described by Trois*), but a little more may

be told about it.

When the organic substances are destructed by 'Eau de Ja-

velle', the ossifications will remain and may easily be studied.

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