810 ORIGINAL ARTICLES. 



I may not have succeeded in translating into very terse or elegant 

 language, some of the more complex of the compound German 

 words.— E. P. W.] 



1. — On Aiian gious Retinas. 



In the xxxiii. volume of the " Sitzungsberiehte der naturwiss. Classe 

 der kais. Akademie der "Wissenchafteii zu Wien," I published a trea- 

 tise on hearts devoid of nutritive blood-vessels. (TJeber gefiisslose 

 Herzen). I there demonstrated, by microscopical investigations, that 

 the heart, in all the Amphibia, presents the remarkable peculiarity, 

 that the Arteria coronaria, which arises from one* of the first 

 branches, into which the Bulbus arteriosus splits, and at some dis- 

 tance from the heart, supplies only the Bulbus arteriosus itself ; and 

 that not the smallest arterial branch enriches the muscular substance 

 of the Yentriculus, or of the Atrium cordis. 



I have likewise demonstrated, that the heart of Sauria, Ophidia, 

 and Chelonia, is also partially deprived of blood-vessels ; in them, 

 the outermost layer of the muscular stratum of the heart, possesses, 

 like all the other muscles, a capillary network, but still, the greater 

 part of the heart-mass is entirely destitute of nutritive blood-vessels. 

 This is the case, too, with all the osseous Eishes, while the more 

 highly organised Kays and Sharks have, like warm-blooded ani- 

 mals, the coronary arteries distributed to the whole muscular coat of 

 their hearts. In the paper, alluded to, I have stated the reason why 

 such an apparent anomaly is, in these several cases, quite in accordance 

 with physiological principles ; and I need not further allude to the 

 matter here. My reason for referring to it at all is that I have now 

 met with the same exclusion of all nutritive arteries, in a different 

 organ, and not only is the organ one of similar importance, but it 

 also presents so constantly this state of anangia (a priv. — ayyelor), 

 that the latter becomes almost an anatomical characteristic of certain 

 classes of Vertebrata. 



The retina of all Birds, Eeptiles, Amphibia and Eish, osseous 

 and cartilaginous, contains not the slightest trace of blood-vessels, so 

 that the vascularity of the retina occurs only in the Mammalia. I 

 communicated a short notice of this interesting anatomical fact to 

 the Academy of Sciences in Eebruary, which will not, however, be 

 printed until towards the end of the year (1861), as there are many 

 prior papers for publication. Hence, I have thought, that a note of 

 the existence of these anangious retinas would not be without interest 

 for the readers of the Natural History Eeview. I trust, that those 

 engaged in optical inquiries, will see the importance of this disco- 

 very, for the assertion of physicists, that the blood-vessels of the 

 retina must absorb some of the rays of light, and so cause certain 



* Arteria carotico-lingualis ; miki. 



