116 Miscellaneous. 



takes place within the tissues of the host ; moreover, the enveloping 

 membrane of the cysts of these species is of an extreme delicacy, 

 presenting a contrast vpith the thickness and resistance of the same 

 envelope in the other species previously described, and in which, as 

 we know, development is partially accomplished in the external 

 medium. 



I have since been able to observe similar facts in other species of 

 Coccidiv.m, likewise parasitic in fishes, which have, moreover, 

 enabled me to establish certain interesting peculiarities. 



I met with one of these parasites in the liver of Caranx trachuriis 

 (at Concarneau, Saint-Valery-en-Caux). In the adult state, which 

 alone I was able to observe, it appears in the form of a perfectly 

 spherical cyst, with a mean diameter of 25 ^n, and enclosing four 

 spores without a trace of a residual mass. These spores within the 

 cyst are arranged in very regular fashion crosswise and by two and 

 two, in such a way that the two spores which correspond to the 

 same diameter of the cyst are placed at the same level and above or 

 below the two others. I propose the name Coccidium cruciatum 

 for this species, to commemorate this arrangement, which is con- 

 stant and very characteristic. 



The spores when seen in optical section present an eUiptical or 

 oval contour. They measure on an average 7 to 9 /i in length by 

 6 ju in breadth. Their envelope, which is tolerably thick, is very 

 remarkable on account of its composition ; it is, in fact, formed of 

 two apposed valves, and this has not hitherto been observed in any 

 Coccidiid. All round the spore, in the direction of its greater 

 diameter, we observe a kind of little thickening, marking the line of 

 union of the valves. 



The contents in the fresh state exhibit nothing but large refrin- 

 gcnt globiilcs ; these elements, which represent a residual mass, or 

 " noyau de reliquat," disappear in greater part under the action of 

 reagents, and we are enabled to detect the falciform bodies. In 

 preparations which are not stained or where the stain is non-elective 

 we often fancy we are able to distinguish four of these : this is due 

 to the fact that these elements, which are longer than the spore, 

 are recurved within its cavity ; moreover, at the level of the thick- 

 ening of the case a phenomenon of refraction is produced, which 

 gives the sensation of a solution of continuity in their length. But 

 in reality there exist but two of these bodies, and by studying 

 preparations properly fixed and stained we come to distinguish them 

 clearly, as well as the nucleus of each. 



I have found C. crnciatmn sometimes disseminated in the tissue 

 of the liver, sometimes in little brownish masses enclosing a variable 

 number of cysts, and situated usually in contact with important 

 vessels. 



In the liver of the sardine I have observed another very closely 

 allied Coccidiid. It differs from C. cruciatum only in the fact that 

 the dimensions of the cyst are perhaps slightly smaller and that its 

 spores are never arranged in any order. The latter present pre- 



