316 SUMMARY OF CURRENT RESEARCHES RELATING TO 
Timicates and Echinoderms. M. Pizon discusses, however, the possi- 
bility of adaptation being the cause of the resemblances which he points 
out. In any case he considers that these resemblances are important 
enough to attract attention. 
In his discussion of the phenomena of the formation of colonies, he 
insists on the fact that an adult Botryllid is, at its death, replaced by 
the two ascidiozooids to which it has given rise, and which are each 
accompanied, as was their parent, by two younger and unequally 
developed generations. 
In discussing the phenomena of physiological individuality, the 
author urges that the production of the primitive ascidiodeme by the egg 
itself confirms the laws of Perrier that (1) the egg of an organism that 
makes part of a colony tends to reproduce not only the organism in 
which it is found, but the entire colony of which the organism is 
part, and (2) in proportion as the organisms which constitute a colony 
become more closely one, the eggs which they produce tend to 
reconstitute more and more rapidly the whole of the colony. Attention 
is called to the existence in the Botryllidae of a well-marked vascular 
colonial network ; each new bud always remains in relation by a 
vascular tube (ectodermic pedicel). Thanks to this system of vascular 
tubes colonial life is realized to the highest degree in the Botryllidae ; 
the nutrient elements are shared, not only among the different ascidio- 
zooids of one and the same system, but among all the systems of one 
colony. There would appear to be some community of share in the 
ova produced. 
In the concluding portion of his memoir he deals with the develop- 
ment of the gonads. 
New Respiratory Globulin of Tunicates.* — Dr. A. B. Griffiths has 
discovered a third form, which he calls y-achrooglobin, of this respiratory 
globulin. He has found it in Ascidia , Molgula , and Cynthia ; it exists 
in an oxidized and a reduced state, and 100 grm. absorb 149 ccm. oxygen. 
Canalis Neurentericus Anterior.f — Dr. M. Y. Davidoff noticed 
in his study of the development of Distajplia magnilarva that the place 
where the neuropore closes is not precisely the end of the nervous 
system, and that the latter extends somewhat further forward. In the 
subsequent development of the Ascidian, the anterior extension referred 
to above becomes hollow and opens by a canal into the pharynx behind 
the membrane which still separates the stomodaeum from the gut 
proper. Now this canal is not an hypophysis, for the mouth of the 
Ascidian represents the hypophysis ; it is best described by Kupffer’s 
term “ canalis neurentericus anterior.” 
/3. Bryozoa. 
TJrnatella gracilis.^ — Mr. C. B. Davenport has made a detailed 
study of this interesting Bryozoon. He finds that the segmented stem 
consists of a bilaminate cuticle, the axial portion being formed of 
elongated cells, many of which are vacuolated, and surrounding which 
there is no intercellular substance. The musculature of the stalk 
* Comptes Bendus, cxv. (1892) pp. 738 and 9. 
t Anat. Anzeig., viii. (1893) pp. 301-3. 
X Bull. Mus. Comp. Zool., xxiv. (1893) pp. 1-41 (6 pis.). 
