22 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



of the neighbouring body exercising a pull upon the 

 tissues. It is therefore inferred that in this " Siamese- 

 twin " arrangement there is no communication between 

 the digestive cavities and no direct nervous connection. 



Dr. Roaf made a number of interesting observations 

 on the manner in which Echinus, the Sea-urchin, catches 

 its food and passes it around the body by means of its 

 pedioellarisB, spines and tube feet, and on the movements 

 of the teeth when the desirable particle is approaching the 

 mouth. All of these investigations will be published in 

 fuller detail in a paper to appear shortly. 



Dr. Francis Ward's Photomicrographs. 

 (See Plates II and III, pp. 34 and 35). 



" At the invitation of Professor Herdman, I show 

 (Plates II and. Ill) a few photographs of the early life- 

 history of the plaice taken in the Pish Hatchery at Port 

 Erin in May, 1909, and will describe the methods I em- 

 ployed in making these records of the living specimens. 

 No. 1 shows the Plaice Larva almost hatched, x 25. 



" I noticed that during hatching the tail is frequently 

 used as a fixed point; and then by spasmodic contractions 

 of the back muscles the head and shoulders are made to 

 impinge on the edge of the originally small rent in the 

 egg membrane, until the opening is torn large enough to 

 permit the larva to escape. 

 No. 2 shows the Plaice Larva hatching tail first, x 25. 



"In photographing various larva 1 batching, 1 have 

 observed that certain fish, e.g., the Perch (Perca 

 fluviatilis), which have a very small yolk sac, hatch tail 

 first, then the body, and lastly the head, through a small 

 hole; but with Plaice larva?, as with Salmonoid Alevins, 

 hatching is delayed at the stage shown until the head also 

 breaks through. 



