SPOROZOA: GREGARINIDA. 86l 



bodies or sporozoites, a small quantity of protoplasm remaining as the 

 ' nucleus de reliquat.' The number of falciform bodies in each spore-case 

 is probably a constant one ; eight, as in Clepsidrina, appears to be very 

 general. The falciform body is homogeneous, pointed at one end, rounded 

 at the other, or terminated by a fine process, as in Stylorhynchus, and it 

 has been found to be nucleated whenever properly examined 1 . 



The spores are discharged from the cyst by special tubular sporoducts 

 in Clepsidrina and Gamocystis ; in other instances by its disruption caused 

 by an accumulation of liquid (?), or in Stylorhynchus by the swelling of the 

 pseudocyst. They are set free either perfectly loose or else cohering end 

 to end in chaplets. The escape of the falciform bodies from the spore- 

 case by its dehiscence along one edge has been observed in Stylorhynchus 

 longicollis infesting Blaps when the case was exposed to the action of the 

 digestive fluids of the host. The bodies in question executed movements 

 by bending from side to side. The presence of a small nucleated oval or 

 rounded cell, formed beyond doubt from a falciform body, in the intestinal 

 epithelium of the proper host, the growth from it of a process which 

 gradually projects into the cavity of the digestive tract, the appearance of 

 constrictions dividing the growth into segments (supra\ and the descent 

 of the nucleus into the deuteromerite before the completion of the septa, 

 have been recorded in several Polycistids. The spore oiPorospora gigantea 

 gives origin, according to E. Van Beneden, to a non-nucleated amoeboid 

 ' moner' ; this in its turn to two processes, one of which grows faster or starts 

 earlier than the other. The longer process is vibratile and breaks away; 

 the other becomes vibratile as soon as it has absorbed the remaining pro- 

 toplasm. Each process is termed by Van Beneden a ' pseudofilaria ' ; it 

 turns motionless after a time, developes a nucleus, lengthens, becomes 

 septate and adult. Urocystis ( = Monocystis) Sipunculi is said by Lankester 

 to have a * pseudofilaria J stage, followed by a ' pseudocercaria ' stage, i. e. 

 one with a slender tail and large body like a Cercaria. The body is 

 nucleated, the tail drops away, and its fate is unknown. It must be borne 

 in mind that the life-history of only a few Gregarinida has been traced. 



Longitudinal fission occurs in the young Urocystis Siptmctdi ; trans- 

 verse fission into two or three parts in the adult Monocystis porrecta and 

 M. cuneiformis of the Earthworm, the parts thus formed undergoing 

 encystation at the same time. 



The Coccidiidae are found in various Vertebrata, Mollusca and In* 

 secta ; the Monocystidae chiefly in Urochorda, some Chaetopoda, Gephyrea, 



1 Ruschhaupt maintains that in the Monocystis of the Earthworm the falciform body is a mass 

 of reserve material ; that the rest of the protoplasm grows at its expense. The ripe spore set free by 

 the rupture of the cyst is taken up by an amoeboid spermatospore of the vesicula seminalis. The 

 spore-case slowly thins away, and by growth the spore passes into the adult. Cf. Schneider's critique 

 in his Tablettes Zoologiques, i. 1886. 



