TITLES. 
Gen. Sub. 29 
538. Piersol, G. A. Textbook of normal histology, including an 
account of the development of the tissues and of the organs. 
4th Ed. Philadelphia : 439 pp., figg. 
539. Pitard, E. Sur le Plankton des lacs du Jura. C.R. Soc. Helvet. 
lxxix, pp. 152-155. 
540. Plateau, F. Comment les fleurs attirent les Insectes. Recherches 
experimentales. Deuxieme Partie. Bull. Ac. Belgique, xxxii, 
pp. 505-534, 1 pi. 
541. Plato, J. Die interstitiellen Zellen des Hodens und ihre physio- 
logische Bedeutung. Arch. mikr. Anat. xlviii, pp. 280-304, 1 pi. 
542. Platt, Julia B. Ontogenetic differentiations of the ectoderm in 
Necturus. Study ii. On the development of the peripheral nervous 
system. Quart. J. Micr. Sci. xxxviii, pp. 485-547, 3 pis. 
543. °Poli, C. Sviluppo della vescicola uditiva nei Yertebrati, studio 
morfologico. Genova : 8vo, 99 pp., 4 pis. 
Pollard, E. C. [See Boas (72).] 
544. Poulton, E. B. Opening address. Section d, Brit. Ass. 1890. 
A naturalist’s contribution to the discussion upon the age of the 
earth. Rep. Brit. Ass. 1890, pp. 808-828 ; Nature, liv, pp. 500-509 ; 
Science, iv, pp. 625-037 & 608-080. 
545. . Charles Darwin and the theory of natural selection. London 
and New York : 8vo, viii & 224 pp. 
540. Prenant, A. Elements d’embryologie de I’liomme et des 
Yertebres. T. ii. Organogenic. Paris : xiv & 850 pp., 381 figg. 
4347. Przrihram, Hs. Regeneration bei den niederen Crustaceen. Zool. 
Anz. xix, pp. 424 & 425, 2 figg. 
548. Quinton, M. Les temperatures animales dans les problemes de 
revolution. C.R. Ac. Sci. cxxii, pp. 850-853 ; and in translation, 
Ann. Nat. Hist, xviii, pp. 64-67. See also La Nature, xxiv, 
pp. 154 & 155. 
.549. Rarl, C. Ueber die Entwicklung des Urogenitalsystems der 
Selachier [Zweite Fortsetzung der “ Theorie des Mesoderms 55 ]. 
Morphol. Jahrb. xxiv, pp. 632-767, 7 pis., 32 figg. 
•550. Ramon y Cajal, S. Allgemeine Betrachtungen fiber die Morpho- 
logic der Nervenzelle. Arch. Anat. 1890, pp. 187-201. 
551. . Sobre la fagocitosis de las plaquetas de los vertebrados 
inferiores. An. Soc. Espan. xxv, pp. 5-12, 2 figg. 
552. . Estructura del protoplasma nervioso. T. c. pp. 13-46, 6 figg. 
553. . Nouvelles contributions a 1’etude liistologique de la retine 
et a la question des anastomoses des prolongements protoplasmiques. 
J. Anat. Physiol, xxxii, pp. 481-543, 4 pis. 
554. Rath, O. vom. Zur Kenntnis der Hautsiunesorgane und des sen- 
siblen Nervensystems der Arthropoden. Zeitschr. wiss. Zool. lxi, 
pp. 499-539, 2 pis. 
•555. . Neue Beitrage zur Frage der Chromatinreduction in der 
Samen-und Eireife. Arch. mikr. Anat. xlvi, pp. 168-328, 3 pis. 
550. Rauff, H. Ueber angebliche Organismenreste aus pracambrischen 
Schichten der Bretagne. N. Jahrb. Min. pp. 117-138, 17 figg. 
