34 ALLEN 



roid coat arose from this plexus. The first vokime of Cuvier 

 and Valenciennes' great work on fishes (ii) issued in 1828, con- 

 tains a short general description of the circulation of Pe7'ca, with 

 2 excellent plates, which show practically all the vessels, in- 

 cluding the afferent and efferent pseudobranchial arteries, and 

 10 years later, Jones (41) carefully described and figured the 

 retia mirabilia of the eye. 



About this time marked the beginning of the classical writings 

 of Hyrtl, Miiller, Vogt, and Stannius. Between the years 1838 

 and 1872, Hyrtl published at least 7 different papers on the cir- 

 culation of fishes, but unfortunately I have had access to only a 

 few of them. Miiller (50) tells us that in the first one (30) the 

 author made a microscopical examination of the gill-filaments, 

 and showed that they contained no lymphatic vessels, as had 

 been claimed by some previous investigators. He also explained 

 correctly the course of the blood from the hyoidean artery to the 

 pseudobranchi£e, and from thence to the eye. With Hecht, he 

 noticed the pseudobranchial artery coming from the circulus 

 cephalicus. In 1852, Hyrtl (32) described with considerable 

 detail the arterial S3'stem of Lefisosteits, and 6 years later the 

 arterial system of the roaches (34). One of the best general 

 works on the circulation of fishes is to be found in part IV of 

 Miiller's famous work on Myxinoiden (50), consisting of 130 

 pages and 5 plates. He takes up almost the entire circulator}- 

 system of cyclostomes, selachians, and several teleosts in a com- 

 parative way, going into great detail over the blood suppl}^ of 

 the pseudobranchiae, choroid gland, and air-bladder. Vogt's 

 splendid monograph on the Anatomy and Embryology of the 

 Salmon was published in 1845, but unfortunately I could get 

 access only to the plates, of which several were devoted to the 

 adult, and many others to the development of the circulatory 

 system in the embryo. In Stannius' Handbuch der Anatomie 

 der Wirbelthiere (74), there is a brief, but perhaps the best, gen- 

 eral description of the circulation in the several groups of fishes ; 

 there are, however, no plates. The author does not go into 

 quite as much detail regarding the blood supply of the pseudo- 

 branchia, eye, and air-bladder as Miiller, but goes into more 

 detail concerning the larger trunks and the vascular supply for 

 the visceral organs. 



