244 



Mr. A. E. Shipley. On the Mesohlast [Nov. 2H, 



The facts above recorded are somewhat novel. That they are facts 

 -so far as Peripakus capensis is concerned I have not the slightest 

 doubt. Whether or no they are applicable to other animals is another 

 question. If they are, the following considerations present them- 

 selves : — 



1. Klein's view of the continuity between the reticulum of the 

 nucleus and the reticulum of the extra-nuclear protoplasm receives 

 -striking confirmation. 



2. Metschnikoff's and Lankester's views as to the origin of the 

 gastrula and its gut receives support. 



3. Herbert Spencer's view of the origin of the nervous system may 

 perhaps not be so far from the mark as at first sight appeared. 



4. The connexion between the nerve and muscles and sensory 

 epithelial cells receives its morphological explanation, being due to a 

 primitive continuity which has never been broken. In fact the con- 

 nexion between almost every kind of tissue cell is explicable as 

 being the primitive condition. 



5. There is no essential difference between ducts with perforated 

 cells and ducts with so-called cellular walls (inter- and intra-cellular 

 ducts). 



6. If the protoplasm of the body is really a syncytium, and the 

 ovum until maturity in the ovary a part of that syncytium, the separa- 

 tion of the generative products does not differ essentially from the 

 internal gemmation of a protozoon, and the inheritance by the off- 

 spring of peculiarities first appearing in the parent, though not 

 explained, is rendered less mysterious, for the protoplasm of the 

 whole body being continuous, changes in the molecular constitution 

 of any part of it would naturally be expected to spread, in time, 

 through the whole mass. 



Shortly, these facts if generally applicable reduce the adult body 

 to a syncytium — to a multi-nucleated vacuolated protoplasmic mass, 

 and embryonic development to a multiplication of nuclei and a 

 specialization of tracts in this mass. 



II. " On the Formation of the Mesoblast, and the Persistence 

 of the Blastopore in the Lamprey." By Arthur E. 

 Shipley, B.A. Communicated by Professor M. Foster, 

 Sec. U.S. Received October 29, 1885. 



At the close of segmentation the egg of the Lamprey (Petromyzon 

 planeri) forms a blastosphere. Owing to the way in which the yolk 

 is distributed, the segmentation cavity is rather eccentrically placed. 

 It is roofed in by several rows of small cells, while its floor is com- 

 posed of a few very large cells much crowded with .food yolk. The 



