Misre.lUuu'onx. 193 



particularly aguinst tli« tost in the part which extends between the 

 mouth and the subanal plastron, especially towards tho conical 

 point which iiiferiorly terminates the plastron. It is also t're(|uently 

 observed upon the actinal curvature of the intestine on the inner 

 side. In these regions wo see irregular masses of a shining black 

 colour, the volume of which varies from that of a point scarcely per- 

 ceptible by the naked eye. to that of masses measuring more than 1 

 centimetre iu length and 4 o millimetres in \vidth. Their aspect 

 and consistency immediately remind us of the plasraodia of the Myx- 

 omycetes. On the surface of tho masses there are a variable num- 

 ber of hyaline vesicles, sometimes very small, sometimes from 1 to 2 

 millims. in diameter. In tho interior of these hyalmo spheres 

 there is one or more, rarely several, points of a dead white colour, 

 contrasting vividly with the black tint of the plasmodial masses. 



When examined under a high power, the hyaline vesicles (cysts) 

 appear to be composed of a structureless membrane and to contain in 

 their interior: — (1) a mass of crystals (the dead white point); (2) 

 spores ( Psorospermia^) arranged in an irregular sphere. These 

 spores are situated at the extremities of filaments wliich radiate 

 round a central point, where there i.s a nucleus of a yellowish sub- 

 stance. Each spore is sustained hy two filaments tangential to the 

 extremities of its smaller axis ; and at the first glance it would be 

 supposed that it terminates in a tube with the interior of which it is 

 continuous. Similar filaments have been described by M. Balbiani 

 in the Psorosperraia? of fishes*. The spores are fusiform, 0-006- 

 0-010 millim. in length, 0-0(11-0-002 millim. in breadth. Certain 

 cysts furnish much smaller spores (microspores), a few others larger 

 spores (gigaspores). These microspores and gigasporcs are more in- 

 flated towards the middle than the typical spores. In other respects 

 the dift'erent varieties of spores behave in the same manner, except 

 that it appeared to mo that the microspores are preferently produced 

 in the smaller cysts. In the large cysts, at the moment of maturity, 

 the spores affect an arrangement very different from that just de- 

 scribed in the young cysts, or in those which arc too small to permit 

 a dis])lacement of contents : when such a displacement is possible 

 the lilaraents cease to adhere to the central point and the spores 

 unite by their peripheral part to form a great number of little groups ; 

 at the same time the filaments become applied to each other, so as to 

 constitute a sort of flagellum three or four times as long as the spore. 

 The little groups then have the appearance of colonies of Flabellata ; 

 but the pseudoflagellum of each spore remains always motionless. 

 The adhesion of the spores to each other is due to a secretion which 

 is produced in a sort of little cup which terminates tho spore on the 

 side which was previously ])eripheral. 



By examining, with the Hartnack objective No. 9, the spores that 

 have issued from different cysts, the whole series of development 

 may be verj- ciisily obtained — some containing merely a gran-jlar 

 protoplasm, the others presenting from I^ to (> falciform corpuscles in 



« Coniptes Kendus. Jul\ 2()th. lH»i'{. 



