86 E. RAY LANKESTER, ON GREGARINIDA. 
been deceived, the idea of the Gregarina being a simple 
organic cell is at once exploded.” 
I have carefully examined the Gregarina Blattarum with 
Powell’s 1, and Smith and Beck’s 1, and have been able thus 
far to confirm Dr. Leidy’s observations. In the intestine of 
the Blatta orientalis I met with the Gregarine in some 
numbers, presenting to the unassisted eye the appearance of 
semi-transparent whitish globules; when placed under the 
microscope and subjected to slight pressure the sacs appeared, 
containing but few granules, most having escaped through 
the rupture of the membrane. This was seen to be double, 
consisting of a transparent external tunic, through which the 
strize on the internal coat were distinctly seen (fig. 20). This 
internal striped tunic appears not to extend to the an- 
terior or cephalic sac, which is entirely without structure, 
and formed only by the external membrane. 
The contents of the sacs were minute, ovoid granules, 
transparent, and presenting, en masse, a. slightly yellowish 
colour. The anterior sac generally contains a less number of 
these granules ; it is not contractile, as the posterior sac, and 
is more easily ruptured. This latter fact may be attributed 
to the absence of the striated tunic. In fig. 13, the striated 
appearance of the inner tunic is represented, the lines are 
nearly the =;5,5,th of an inch apart. Figs. 9, 10, 11, are 
various forms of the Gregarina Blattarum which I have met 
with. In fig. 18, the nucleus is drawn as it appears when 
extruded from the posterior sac. Occasionally there are two 
such bodies lodged in the granular mass. The partition 
which divides the anterior from the posterior sac is structure- 
less, and is probably an inversion of the external membrane. 
All communication between the anterior and posterior sacs is 
cut off by this membrane. 
In the ‘ Mémoires de l’ Académie Royale de Bruxelles’ for 
the year 1854, an elaborate and beautiful paper, by M. 
Lieberkiihn, copiously illustrated, appeared, describing his re- 
searches on the Gregarine of the earthworm. The author does 
not express any very decided opinion upon the two questions 
which have been discussed by Leidy and Bruch ; but devotes 
the principal part of his memoir to the development and re- 
production of the Gregarine. He, however, mentions that 
he has seen longitudinal striations on the membrane of some 
forms, and figures them, but is uncertain as to whether 
they are structural, or due only to contraction. With regard 
to the development of Gregarinz into filaria-like worms, 
which Bruch, who made his observations chiefly on the Gre- 
garina Lumbrici, thought probable, M. Lieberkiihn says but 
