1903.] NATURAL SCIENCES OF PHILADELPHIA. 55 



der, it is a large rounded mass; but whereas Schneider's figures repre- 

 sent it to be sohd, I find that it contains, at least in some cases, a large 

 cavity. Within this cavity was a fluid in which floated a few granules. 



This condition was the more usual, and free gregarines. as they moved 

 about on the slide, presented a remarkable appearance with their enor- 

 mous balloon-shaped protomerites. The appearance of other indi- 

 viduals was, however, markedly different. Fig. 17 shows an attached 

 animal. Here the protomerite was narrow and elongated, the narrow 

 anterior end being, so far as I was able to see, embedded in the cells of 

 the host. In this case there were no indications of a cavity within the 

 protomerite. 



It is to be observed, in figs. 15, 17 and 18, that the septum dips back- 

 ward. In a number of cases, however, the septum dipped forward, and 

 such appears to have been the only condition seen by Schneider. In 

 these gregarines, accordingly, the septum may dip in either direction, 

 which indicates a high degree of flexibility and elasticity on the part of 

 the sarcocyte, and this condition is also suggested by their superlative 

 polymorphism. 



It is therefore possible to interpret the rather curious appearance 

 shown in fig. 16. This was drawn from a progressing individual, to all 

 appearances wholly normal. In this animal, the protomerite lies 

 embedded within the deutomerite. It may be suggested that this is 

 derived from the condition shown in fig. 18 by a mere contraction of the 

 most anterior part of the deutomerite, by which the protomerite is 

 forced backward. Quite a number of animals presented this appear- 

 ance. 



Fig. 18 is from a permanent mount, and probably represents the 

 normal form of the protomerite when only a small quantity of fluid is 

 present. It is noteworthy in that the protomerite is more densely 

 granular than the deutomerite. 



The larger, more elongated specimens reached a length of 425 

 microns. There were about 25 gregarines in the beetle-larva, which 

 was taken at Wyncote, Pa. 



Actinocephalus dujardini Aime Schn. 



Actinocephalus dujardini Schneider (1875), p. 589, PI. 16, figs. 9-20. 

 I have seen this little gregarine several times in specimens of Litho- 

 hius forcipatus. 



Hoplorhynclius actinotus Leidy. PI. Ill, figs. 36, 37. 

 Gregarina adinotus Leidy (1889), p. 10,1 &g. 

 Epimerite : Amphora-shaped. Differentiated in front into four 



