746 



TllANSACTIONS OF SECTION D, 



to it in Struthio, Dollo, indeed, called attention to reptilian epiphyses so far 

 back as 1884. Albrecht also noted these in sections of the upper and lower 

 ends of the femur of Phrynosoma Harlanii (Schwalbe's collection). Sauropterygids 

 have large epiphyses in both ends of the femur and humerus (Reynolds) and 

 the humerus in Sauropterygia (Zittel). Anomodontia have also epiphyses 

 (A. S. Woodward). In Monitor both tibia and fibula have proximal and distal 

 epiphyses. The tibia seems to have two proximal and the fibula two (perhaps). 

 There are epiphyses for the head, great trochanter, and lower end of the femur. 

 Shell-like structures, like calcified fibrous tissue, are present near the lower joint. 

 There are epiphyses for the head and tuberosity of the humerus. There are three 

 or four separate shell-like structures below. The radius and ulna have each two 

 epiphyses. 



Ossification is favoured amongst other things by rest ; the previous deposit of 

 calcareous matter favours this. Cartilage, which is compared with a bufier in the 

 case of the extremities of long bones, will if the cartilage be sufficiently thick, 

 have probably its least mobile part near the central plane, perpendicular, trans- 

 verse to the lines of pressure. It is possible that further investigation will lead to 

 an increase in the number of Sauropsids known to have epiphyses. (See ' Journal 

 of Anatomy ' and ' Anat, Anzeiger,' 8,) 



12. Tlte Development of Littorina littorea. By W. M, Tattersall. 



1 3. The Digestive Enzymes of Invertebrates. By Dr. Herbert E. Roaf. 



The presence of various hydrolytic enzymes has been sought for in a number 

 of invertebrates. Methods used. Protein digestion by total nitrogen determina- 

 tions after precipitating by trichloracetic acid, and by congo red fibrin. 



Hydrolysis of polysaccharides and saccharose by coloration with iodine and 

 reduction of alkaline copper solution. 



Hydrolysis of maltose and lactose by Barfoed's reagent. 



Lipase and rennin by litmus milk. 



Fibrin ferment (?) by oxalated plasma from pig's blood. 



Protein digestion at different temperatures showed, in practically all cases, 

 increase in activity up to 40° C. ; and with varying amounts of acid or alkali it 

 was found that the maximum of digestive activity occurred with lower strengths 

 than are necessary for mammalian pepsin or trypsin. 



The enzymes were prepared by treating the fresh minced tissue with an equal 

 weight of glycerine, and after keeping for some time the extracts were strained 

 through cotton. Certain of these extracts were precipitated by alcohol, and the 

 coagulum extracted with water. The method of preparation appeared to affect 

 the nature of the proteoclastic enzyme found. 



The following results were obtained, using glycerine extracts of fresh tissues. 

 Protein digestion by nitrogen determinations : — 



