174 REPORT OF THE COMMISSIONER OF FISH x\ND FISHERIES. 



4. Genus et sp. incert. PI. 4, fig. 1. 



Eutozoan of Salmo fav'io, Valentin, Ueber ern Entozoon im Blute vou Salmc 

 fario, Miiller's Arcliiv., 1841, pp. 435,436, pi. 15, fig. 16; ih. Leydig, 1851, 

 Miiller's Archiv., pp. 11,12; cf. Davaino, Traite ties Eutozoaires, Paria, 

 1860, p. III. 



Amoeboid stage. — In blood obtained by pnucture of the abdominal 

 aorta of Salmo fario (brown trout) Valentin found, besides tlie blood 

 corpuscles, some dark globules similar to round pigment cells. They 

 have a quick, tremulous motion, also a definitely locomotive one. 

 Observed for some time, a clear "tail" comes into view, which later 

 elongates; there thus becomes revealed an elougate animal with a rapid 

 motion, mostly of rotation, effected by 1 to 3 variable processes of one 

 side of the body. Anterior and posterior parts clear; middle portion 

 containing numerous dark corpuscles, perhaps pigment particles which 

 it had eaten. When rolled up into a ball it often had the appearance 

 as though each club-shaped process of the body contained one of the 

 globules (pi. 4, fig. le). No finer structure could be detected. Size 7-5 

 to 12-5 yw. Sometimes a round opening appeared to be present at the 

 anterior end. The posterior end is somewhat striate. The variable 

 processes always appear in the drawing as they would be seen in the 

 microscope on the right side. Perhaps the club-shaijed peduncles are 

 to be reckoned as such. In drawn blood they remain living from 6 to 

 8 hours. 



Nature. — These bodies are, Valentin says, probably referable to Pro- 

 teus or to Amoebn,, of which they certainly form a new species, different 

 from all of Ehrenberg's. Doubting at first whether these organisjns 

 really belonged to the blood, Vaientin investigated the whole fish. He 

 failed to find, either on the peritoneum, or in the kidneys, intestines, 

 air bladder, brain, etc., any trace of these infusorial Entozoa. Only 

 in the fourth ventricle (the favorite seat of the microscopic intestinal 

 worms) did he find a single specimen. On the contrary, they were so 

 numerous in the blood that often a single droplet contained 10 or more. 

 The blood itself presented nothing worthy of note. The fishes examined 

 showed numerous examples of Ascaris ohtuso-caudata Zeder. No other 

 intestinal worms were found. 



Leuckart^ says: 



Still less is the gregarine nature of the entozoan found by Valentin in the blood 

 of the trout to be mistaken. 



Lieberkiihn regarded it as an amoeba. It could not, he says, be a 

 Gregarine, as it lacks a nucleus.^ 



Although this form has been referred to the Myxosporidia by Leydig, 

 the evidence to sustain such reference is wanting, and at present its 

 myxosporidian affinities can not be regarded as proven. 



1 Archiv. f. physiol. Heilkde, 1852, xi, p. 431. 



^Muller's Archiv., 1854, pp. 11, 12. For Lieberkiibn's subsequent change of view 

 as to the necessity of the presence of a nucleus in the Gregarines, see pp. 95, 96. 



