250 PROCEEDINGS OF THE ACADEMY OF [1896. 



173 — The byssus of the young of the common clam {Mija arena- 

 ria). Amer, Nat., 1889, pp. 65-67 ; abstr. in Jour. Roy. Mic. Soc, 

 1889, p. 375. (The byssus gland is at the base of the foot and the 

 clams are bound together partially by byssus threads and partly by 

 fibres from Ascidians). 



174 — The polar differentiation of Volvox and specialization of 

 possible anterior sense organs. Amer. Nat., 1889, pp. 218-221. 



175 — The quadrate placenta of the common red squirrel. Amer. 

 Nat., 1889, pp. 271-274. 



176 — The origin and meaning of sex. Amer. Nat., 1889, pp. 

 501-508. 



177 — Notes on the development of Ampullaria depressa Say. 

 Amer. Nat., 1889, pp. 735-737. (Description of eggs, etc.). 



178 — Karyokinesis in larval Amhlystoma. Amer. Nat., 1889, 

 pp. 827-829. (Pointing out the clearness of the karyokinetic pro- 

 cesses). 



179 — On a brood of larval Amphiuma. Amer. Nat., 1889, pp. 

 927-928. 



180 — The acquisition and loss of food-yolk and origin of the cal- 

 careous egg-shell. Amer. Nat., 1889, pp. 928-933. (Interpreta- 

 tion of the various ways in which surplus nutriment is elaborated 

 into numerous small eggs or into fewer and larger ones, or diverted 

 to the embryo itself). 



181 — The i^hylogeny of the sweat glands. Proc. Amer. Phil. 

 Soc, 1889, pp. 534-540. 



182 — Proofs of the effects of habitual use in the modification of 

 animal organisms. Proc. Amer. Phil. Soc, 1889, pp. 541-549. 

 (The principle of over-nutrition was at once the cause of sexuality, 

 the struggle for existence and the direct means of evolution of all 

 larval forms. Over-nutrition, resulting in sexuality, was the means 

 of heaping up potential physiological energy in the egg, so as to ren- 

 der larval development and a larval struggle for existence a possi- 

 bility. The mainspring of evolution or its motive force is to be 

 sought in sexuality). 



183 — A physiological theory of the calcification of the skeleton. 

 Proc. Amer. Phil. Soc, 1889, pp. 550-558. 



184 — Evolution of the specialized vertebral axis of the higher 

 types. University Med. Mag., April, 1889. 



185 — The function and histology of the yolk-sac of the young 

 toad-fish (Batrachus tau). Proc. Acad. Nat. Sci. Phila., 1890, pp. 

 407-408. 



186 — A physiological hypothesis of heredity and variation. 

 Amer. Nat., 1890, pp. 85-92. 



187 — The continuity of the primary matrix of the scales and the 

 actinotrichia of teleosts. Amer. Nat., 1890, pp. 489-491. 



188 — The eye, ocular muscles and lachrymal glands of the shrew 

 mole (Blarina talpoides Gray). Proc. Amer. Phil. Soc, 1890, pp. 

 16-18. (Calling attention, among other points, to the slight attach- 



