PROTOZOA AND OTHER ANIMALS 899 



consumes the soft parts of the parenchyma and blood cells. Penard con- 

 sidered that it may be a temporary parasite only, and is closely related 

 to G. " pyrijortne." 



There is one record of a similar ciliate in the tissues of a vertebrate. 

 Epstein (1926) studied an infection of very young fish, Ahramis brama 

 L., with Glaucoma, probably G. pyrijormis according to Lwoff (1932). 

 Tv^'o to three percent were naturally infected in an aquarium at a lake 

 near Moscow. The infection began with the yolk sac, which the ciliates 

 reached through the gut. They then entered the heart and spread 

 throughout the vascular system. In two or three days the hosts suc- 

 cumbed, with all except the resistant parts consumed. The ciliates oc- 

 curred in great abundance in the canal of the spinal cord. 



Related ethologically to the invasion of the bodies of aquatic larvae 

 of Nemocera by G. pyrijormis or related ciliates is the occurrence of 

 the common marine ciliate, Uronema marinum Duj., in the coelom 

 of a sipunculid. Madsen (1931) mentioned the observation by Mrs. 

 E. Wesenberg-Lund of masses of ciliates in several Halicryptus sp/nulo- 

 sus that had been kept in Copenhagen for several months without food. 

 After some days the sipunculids died, and the ciliates lived longer in 

 the cadavers. He regarded this invasion as following a bacterial infec- 

 tion, Urone??/a feeding on the bacteria, but did not suggest how the 

 ciliates may have entered Halicryptus. 



Accidental parasitism similar to that of G. pyrijormis is the relation- 

 ship of Anophrys sarcophaga to crabs, noted by Cattaneo (1888) and 

 studied exhaustively by Poisson (1929, 1930). This marine ciliate 

 normally lives in decomposing animal matter. Under certain circum- 

 stances it invades the hemocoele of Carcinus maenas, but natural in- 

 fection is rare. Cattaneo found it in one of 300; Poisson in 7 of more 

 than 3,000 at the biological station of Roscoff. The ciliates multiply ac- 

 tively in the blood, consuming the amoebocytes, and when these are 

 exhausted feeding on plasma. When the host dies, the ciliates devour 

 bacteria and fragments of tissue, surviving for some hours until de- 

 composition is advanced, when they encyst or die. 



Artificial transmission was easily accomplished. Of 25 Carcinus maenas 

 inoculated, 20 died within 7 days, usually with a massive infection. Five 

 crabs survived and soon lost the ciliates. Attempts were made to inocu- 

 late 7 other crabs of the genera Cancer, Portunus, Maia, and Eupagurus. 



