OF MASSACHUSETTS. 



139 



11. Clark, A. H. The Fisheries of Massachusetts. In the Fisheries and 



Fishing Industries of the United States, United States Fish Commis- 

 sion and Tenth Census, 1887. 



12. Smith, H. M. The Giant Scallop Fishery of Maine. United States 



Fish Commission Bulletin for 1889, Vol. 9. 



13. Howell, W. H. A Text-book of Physiology, 1909. 



14. Langworthy, C. F. United States Department of Agriculture, Farmers' 



Bulletin 85, 1898. 



15. Sharp, B. Eemarks on the Phylogeny of the Lamellibranchiata, Proc. 



Acad. Nat. Sc., Phila., 1888. 



GLOSSARY. 



Adductor muscle, . Muscle which draws the two valves (shells) to- 

 gether. 



Anterior, . . . Front. 



Archenteron, . . Primitive or original digestive tract. 



Asymmetrical, . . Not symmetrical. 



Auricle, . . .A chamber of the heart. 



Bathymetrical, . . Eelating to the depth in the sea. 



Blastopore, . . . The opening into the archenteron. 



Blastula, . . . An early stage in the development of the embryo, 

 in which the outer cells form a definite layer. 



Byssus, . . . Thread-like fibers secreted by the foot for attach- 

 ment. 



Cell, . . . . The unit structure of life. 



Cilia, .... Filamentous protoplasmic processes. 



Cleavage, . , ;, Natural division of the egg cells. 



Cloacal chamber, . Space into which waste material is discharged be- 

 fore passing out the excurrent siphon. 



Crystalline style, . A transparent gelatinous rod which lies along the 

 upper part of the intestine. 



Cytoplasm, . . . That part of the protoplasm outside of the nucleus. 



Diatoms, . . . Microscopic plants, which constitute the food of 

 the shellfish. 



Dimyarian, . . . Having two adductor muscles, as the quahaug. 



Dissoconch, . . Literally, two shelled; babyhood shell with no pli- 



cations. 



Dorsal, . . . Referring to the back of the animal but not neces- 

 sarily the upper side. 



Ectoderm, . . . The external outer layer of cells. 



Egg, .... The female germ cell ovum. 



Egg capsule, . . Case in which the egg is inclosed. 



Embryo, . . . The first rudiments of an organism. 



Endoderm, . . . The inner cell layer. 



Equilateral, . . Having all sides equal. 



Equivalvular, . . When two valves are alike in size and shape. 



Exoskeleton, j^. . Outside framework or support, differing from a 

 true skeleton or endoskeleton, which is inside 

 the body. 



