CIRCULATORY SYSTEM. 581 



themselves pierced by very numerous orifices, and so on successively, 

 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 con- 

 sidered 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 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 emunc- 

 tories, through which some principle separated from the blood is dis- 

 charged from the body through the pores upon their surface a suppo- 

 sition rendered more probable, seeing the abundant mucous secretion 

 that may be extracted from them by pressure. " However this may be," 

 observes Cuvier, "it is certain 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 traverses ; and, on the other hand, on inflating the cavity from 

 the branchial chamber, it often happens that the vein becomes filled 

 with air." 



(1556.) Mayer* not only adopts the last of the above-mentioned 

 suggestions 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 urinary secretion ; 

 so that, according to this view, the anatomist referred to does not scruple 

 to designate the chamber called by Professor Owen the "pericardium" 

 as a urinary bladder ; and to the two orifices leading from thence to the 

 cavity in which the branchise are lodged he would assign the name of 

 urethra. Professor Owen has suggested that, in addition to their sub- 

 serviency to secretion, these appendages to the veins of Cephalopods 

 may be provisions for enabling their sanguiferous system to accommo- 

 date itself to those vicissitudes of pressure to which it must be con- 

 stantly subjected, and that they bear a relation to the power possessed 

 by these animals of descending to great depths in the ocean, thus 

 answering the same purpose as the capacious auricle and the large 

 venous sinuses that terminate in the heart of fishes. According to this 

 * Analecten fur vergleichenden Anatomie. 4to, 1835. 



