360 Chronicles of Science. | April, 
to coat them with the solution, but the whole block must be impreg- 
nated with the solution by hydraulic pressure. 
Dr. J. D. MacDonald has communicated to the Royal Society of 
Edinburgh a memoir on the morphology of the tunicated mollusca, in 
which he considers that the fixed tunicates exhibit at least two well- 
marked types, and the free Pelagic group four, which are equally dis- 
tinct and of equal importance. He also considers that very striking 
representative relationships exist, between the fixed and free tunicates, 
as, for example, between Appendicularia and Pelonaia,—Doliolum and 
the remaining simple tunicata, Salpa representing the social, and Pyro- 
soma, the compound group, especially the Botryllians. 
Professor Allman has just poimted out a curious and important 
character of the so-called nemataphores in the plumularian zoéphytes, 
hitherto unnoticed. In Plumularia cristata he finds them to consist of 
a true sarcode or protoplasm, and except in the fact that the proto- 
plasm contains a cluster of thread cells immersed in its substance, it 
appears in no respect to differ from that which constitutes the substance 
of anameeba. This soft granular mass has the power of projecting 
extensile and mutable processes, consisting of a finely granular sub- 
stance which undergoes perpetual change of form, comporting them- 
selves in every respect like the pseudopodia of an amceba, which they 
also resemble in their structure, for they consist of a simple protoplasm 
composed of a transparent semifluid basis, in which minute corpuscles 
are suspended. In Antennularia antenninia, a genus possessing the 
closest affinities with Plumularia, entirely similar phenomena have been 
witnessed, the processes being usually simple, in only one instance there 
having been seen what appeared to be a short irregular branch given 
off from the finger-like pseudopodium. 
M. Lacaze-Duthiers, who, we have observed, has obtained the 
Bourdin prize for his inquiry into the anatomy and physiology of 
corals, has produced a monograph of 371 pages, accompanied by 
another of 20 pages, comprising 120 figures relating solely to corals. 
He describes and draws in detail the reproductive organs, male and 
female, and has studied the development of the eggs, spermatozoids, 
and larve ; has observed the larve during their period of liberty, de- 
termined the first signs of their future transformation, and followed 
this transformation step by step to the moment when the single being 
issuing from the single egg, begins to shoot, and gives birth succes- 
sively to a whole colony, of which it is the actual parent. These 
facts are all new. Coral does not present the phenomena of alternate 
generations, established among so many other Radiata ; still it enters 
none the less into the category of geneagenetic animals, as they are 
termed by M. de Quatrefages. The scolex alone undergoes a real 
metamorphosis. In general the sexes are distinct in corals, but one 
may occasionally find on a male stem a branch where the polyps are 
female, and vice versd. A branch may also contain individuals of both 
sexes, and more rarely still the same individual may be both male and 
female. Thus, regarding the separation of the sexes, the coral zoéphytes 
present the two extremes and almost all the intermediate degrees. 
