CONTENTS OF No. 230.-New Series. 
MEMOIRS : 
PAGE 
Two New Species of the Phoronidea from Vancouver Island. By 
H. L. M. PixELL, B.Sc., F.Z.S., Demonstrator of Zoology and Eeid 
FelloWj Bedford College, University of London. (With 16 Text- 
figures) ....... 257 
Transverse Segmentation and Internal Differentiation of Chromo- 
somes. By W. E. Agak, Glasgow University. (With Plates 12 
and 13) . . . . . . 285 
Studies on the Development of Echinoidea. II. The Early Larva 
of Echinocardium cordatum and the Result of Crossing this 
Species with Echinus esculentus. By Prof. E. W. Macbbidb, 
D.Sc., LL.D., F.R.S., Imperial College of Science and Technology, 
South Kensington. (With Plates 14 and 15) . . . 299 
The Experimental Hybridisation of Echinus miliaris, Echinus 
esculentus, and Echinus acutus. By G. Debaibieux, 
Assistant in Zoology at the University of Louvain (Belgium). 
(From the Imperial College of Science and Technology, London.) 
(With Plate 16) . . . . . .325 
On Paternal Characters in Echinoid Hybrids. By Cresswbll 
Shearer, Walter De Morgan, and H. M. Fuchs. (From the 
Laboratory of the Marine Biological Association, Plymouth.) (With 
Plates 17 and 18 and 4 Text-figures) .... 337 
On the Morphology of the Leishmania of Italian Kala-Azar. 
Third Communication: Cytological Researches on Leishmania 
in Cultures. By Dr. Arrigo Visentini. (From the Zoological 
Department of the Lister Institute of Preventive Medicine and 
the Institute of Comparative Anatomy of the University of Rome.) 
(With Plates 19 and 20) ..... 353 
The Transmission of Leishmaniosis by means of Cultures, and the 
Mechanism of the Natural Immunity in Bats and Guinea-pigs. 
By Dr. Arrigo Visentini. (With Plate 21) . . . 373 
Herpyllobius arcticus. By Kathleen Haudon. (With Plate 
22 and 4 Text-figures) ..... 385 
