52 MANUAL OF ZOOLOGY. 



" pseudonaviculse ") (fig. 2, c}. The next step in the process 

 consists in the liberation of the pseudonavicellae, which escape 

 by the rupture of the enclosing cyst (fig. 2, d}. If they now 

 find a congenial habitat, they give origin to little albuminous 

 or sarcodic masses, which exhibit lively movements, and are 

 endowed with the power of throwing out and retracting little 

 processes of the body which closely resemble the " pseudo- 

 podia " of the Rhizopoda ; so that the pseudonavicella in this 

 condition is very similar to an a.d\AtAmozba (fig. 2, e). Finally, 

 these amcebiform bodies are developed into adult Grcgarince. 

 It will be seen from the above that the formation of the 

 pseudonavicellae out of the granular contents of the body, 

 subsequent to the disappearance of the nucleus, presents some 

 analogy to the segmentation of the impregnated ovum which 

 follows upon the dissolution of the germinal vesicle. In Gre- 

 garina gigantea of the Lobster the embryo is a little mass 

 of sarcode, quite like an Amoeba except that it wants a 

 nucleus and contractile vesicle. It soon gives out two little 

 contractile processes or arms, which become detached and 

 move about like, little worms, when they are termed " pseudo- 

 filariae," from their resemblance to free hematoids. After a 

 period of activity, the pseudo-filarian becomes quiescent, 

 shortens its dimensions, develops a nucleus and nucleolus, and 

 becomes an adult Gregarina. 



PSOROSPERMI^E. There occur as parasites on and within 

 the bodies of fishes certain vesicular, usually caudate, bodies, 

 termed Psorospermice, the exact nature of which is very pro- 

 blematical. According to Lieberkiihn they occasionally give 

 origin to amcebiform bodies, similar to those which are libe- 

 rated from the pseudonavicellae of Gregarinidce. In this case 

 they should probably be regarded as the embryonic forms of 

 some Gregarina. By Balbiani, however, they are looked upon 

 as properly belonging to the vegetable kingdom. 



