ARCHER, ON ASTERIDIA. 185 
strict sense of the word. But here, in the case in question, 
though these Asteridia were with green contents, like 
the other forms hitherto noticed, the fact of the original 
contents of the Penium seeming to have become in most 
instances all absorbed, or, if not all absorbed, the residue 
becoming quite effete and brown, seems to speak for their 
actual parasitic nature. 
It is true that Itzigsohn has sought to establish that these 
** Asteridia,” as well as the very different bodies he calls 
“‘ Spermatospheeria,” are not parasitic, but to be regarded as 
forming a part of the fructification of the plants in which 
they occur; that they, in fact, represent the male element, and 
that their contents exert a fertilising influence on the re- 
mainder of the contents of the original cell in which they 
occur ; nay, he even circumstantially explains the process by 
assuming that the spines are tubules through which permeate 
whatever the influence may be which -is supposed to 
emanate from the “ Asteridium” to the remainder of the 
contents of the original cell—a curious fertilisation truly, 
which in Pentium digitus kills what it acts upon. This fancy 
seems to find a kind of parallel in Hassal’s somewhat similar 
assumption, that the nucleus in Spirogyra is the male organ, 
the fertilisation of the parietal contents being assumed by him 
to be effected in some unexplained way through the agency of 
the protoplasmic threads radiating therefrom.* But these as- 
sumptions need nowadays, I should think, no refutation ; 
Pringsheim has long demolished several of Itzigsohn’s hypothe- 
ses. The fact is that, while imagination has been largely drawn 
upon to find a reproductive process in Conjugate, the true 
one has been overlooked and been regarded as simply a 
fortuitous or insignificant act. Because the process of conjuga- 
tion is so common and so simple, it is ignored, though the 
many grades and phases, in the various types which it pre- 
sents, speak loudly, as it seems tome, for an acknowledgment 
of its true significance. 
Although, then, this crude note possesses no value in 
assisting to throw a further light upon these problematic 
structures, yet perhaps it may not be considered altogether 
without interest, for the following three reasons :—(1) That 
their strictly parasitic nature in this instance seems to be 
rendered very probable by reason of the destruction of the 
Penium during their formation; (2) as being the first instance 
(so far as I am aware) of the occurrence of “ Asteridia” in 
the Desmidiee ; and (3) as being of a form and size not 
before noted in any of the various Asteridia recorded (fig. 4). 
* «British Fresh-water Alge,’ Intr., p. 6. 
