1922] Proceedings of the Academy of Science 11 



only a virtual blastopore lip. that is. laterally and ventrally the 

 ectoderm and yolk cells are not set oft from one another by a groove. 

 This virtual blastopore lip which on the concrescence hypothesis con- 

 tains the material destined to form the axial organs of the embryo, 

 graduaUij closes along the ventral surface of the tail and at the 

 posterior end of the body. This fact forms additional evidence for 

 the view that concrescence, although it may occur in teratological 

 embryos, is not a constant or basic process in the embryogeny of a 

 vertebrate body. 



The recorded observations on the Phloeodictyine sponges leave 

 in doubt the question whether the tubes (fistulae) which project 

 from the body carry the currents of water outwards, inwards, or 

 perhaps in both directions. A specimen of Phloeodictyon putridosum 

 taken by U. S. Bureau of Fisheries Steamer Albatross, in the Philip- 

 pines, seems to answer this question, which no one has yet had the 

 opportunity of studying on the living sponge. The specimen referred 

 to is spheroidal, 115 mm. in diameter, and bears about forty fistulae 

 on its upper and lateral surfaces. Just beneath the natural sur- 

 face of the body a calcareous alga, one of the Corallinaceae, of branch- 

 ing, filamentous habit, has formed a practically solid calcareous layer 

 5 mm. thick. This laj^er, interrupted only by the fistulae, extends 

 all over the sponge body. The interior of the sponge is thus left 

 in connection with the surrounding water only through the fistulae, 

 which, it is therefore obvious, must conduct currents both inwards 

 and outwards. 



The Stems of Grape Hybrids. C. F. Williams. 



A study of transverse and longitudinal sections of mature one- 

 year wood of Vitis vinifera, Y. rotundifolia and their F^ hybrids 

 shows the pattern of the phloem tissue and the character of the 

 cork cambium to be specific. In V. vinifera the pattern is square in 

 outline with alternate tangential layers of hard and soft bast, promi- 

 nent cork cambium and a large sclerenchyma bundle externally. The 

 rays extend intervascularly without expansion, the open ends acting 

 as lenticels. In Y. rotundifolia the pattern is triangular, the hard 

 bast outlining the soft radially, with a small sclerenchyma bundle 

 inside the cork cambium. The rays expand in the vascular region 

 by tangential division. Typical lenticels are present and the cork 

 cambium inconspicuous. The F^ hybrids of this cross show inter- 



