39] STUDIES ON GREGARINES—KAMM 39 



at septum. 400 to 500/i in length. Ratio LP:TL::1:6 (primite) 

 1 :8 (satellite). WP:WD::1:5. Protomerite clear with large chro- 

 midial inclusions and crescentic apical area. Deutomerite dense, nucleus 

 not seen in vivo, spherical, one or more karyosomes. 



Cysts 150/* in diameter. Spores ellipsoidal with faint equatorial line, 

 6.4 by 5/x. 



Intestine and gastric caeca of Pachygraspus marmoratus Fabr. (Cancer 

 depressus). 



Taken at Cavaliere, France, Naples, etc. 



This is recognized as the earliest known species of Gregarines. Redi 

 in 1708 found a parasite in the crab Cancer pagurus but Leger and Duboscq 

 (1908) say: 



La courte description et les images que Redi (1708) donne des vers du Cancer pagurus ne peu- 

 vent s'appliquer aux Gregarines des Crustaces, dont la d6couverte revient k Cavolini, quo- 

 iqu'en aient pens6 Diesing (1851) et Labb6 (1899). 



Cavolini in 1787 discovered in "Cancer depressi" a parasite which he 

 did not name and which Rudolphi (1810 and 1819) placed among his 

 "vermes generis dubii," suggesting that it may be a Distome. 



Diesing (1851) named the parasite Gregarina conformis. In the same 

 paper he named another species seen by the same earlier workers Gre- 

 garina praemorsa. Hence either species might with equal right be named 

 the type species. Diesing (1859) remarks only "Individua solitaria 

 (Cavolini)." 



Frenzel studied the species at length and gives several figures. The 

 above description is taken mostly from his work. 



Leger and Duboscq studied it again and find in their specimens that the 

 satellite is the longer, while the primite is short and relatively stouter. 

 The nucleus in their specimens is subspherical to ovoidal. Dimensions of 

 the two descriptions compare favorably, an association given by the later 

 workers as 1050/i in length, 400/i for the primite, the former being 80/i 

 wide and the latter 40^. Ratios of drawing of the latter's work are as 

 follows: LP:TL::1 : 9 (primite) 1 : 21 (satellite); WP : WD :: 1 

 : 1.5 to 1 : 1.2. Thus their specimens conform to the type. 



In 1907 these workers report schizogonic stages encountered in the 

 coelom. They also found sporogonic encystment in the intestine with 

 cysts 150/1 in diameter found in the excrement and two sizes of spores, 

 6.4 by 5/1 and microspores 5/i by 4.7/i. 



