454 CEPHALOPODA. 



are of a yellow colour, and, when squeezed, they give out an opaque 

 yellowish mucosity ; * but the most interesting circumstance con- 

 nected with these bodies is, that they communicate by large and 

 patulous apertures with the interior of the veins to which they are 

 adherent. The short canals derived from these apertures are 

 themselves pierced by very numerous orifices, and so on succes- 

 sively, until each of the spongy bodies referred to is permeated 

 internally by a multitude of short vessels leading one into another, 

 and ultimately into the vein itself. Cuvier supposes, that, seeing 

 it is impossible that these vessels should not be filled with blood, 

 they might themselves be considered as veins; but then their extent, 

 when compared with the very small arteries of the spongy bodies, 

 forbids us to believe that they have no other office than that of 

 bringing back into the general current of the venous circulation 

 blood derived from these arterial ramifications. He suggests, 

 therefore, that they more probably form diverticula, in which the 

 venous blood may become diffused in order to receive, through the 

 intervention of their spongy walls, the influence of the surrounding 

 medium, so that in this way they may be rendered subservient 

 to respiration ; or else it is possible that the orifices in the veins 

 are the openings of excretory canals derived from these appendages, 

 through which they may pour into the vein some substance derived 

 from the water in which they float. Lastly, it is conjectured that 

 they may be emunctories, through which some principle separated 

 from the blood is discharged from the body through the pores upon 

 their surface ; a supposition rendered more probable, seeing the 

 abundant mucous secretion that may be extracted from them by 

 pressure. " However this may be," observes Cuvier, " it is cer- 

 tain that the communication between these bodies and the exterior 

 is very open, for, on blowing into or injecting the vein, the air or 

 injection passes very readily into the cavity that the vein tra- 

 verses ; and, on the other hand, on inflating the cavity from the 

 branchial chamber, it often happens that the vein becomes filled 

 with air."" 



Mayer-[- not only adopts the last of the above-mentioned sug- 

 gestions relative to the nature of these spongy appendages to the 

 great veins of the CEPHALOPODA, but ventures to bring forward an 

 opinion that they perform the office of the kidneys of higher 

 animals, and separate from the blood a fluid analogous to the 



* Cuvier, M6moire sur le Poulpe, p. 18. 



f- Analekten fur Vergleichenden Anatomic, 4to. 1835. 



