484 
K. W. MA015RIDK. 
• List of Papers Referred to, 
Krohn. — “ Ueber die Larve von Spatangns piirpnreus,” ‘ Miiller's 
Archiv,’ 1853. 
MacBride, E. W. — “The Develoxnnent of Echinus esculentus. 
Together with some Points in the Development of E. miliaris 
and E. acntus,” ‘Phil. Trans. Roy. Soc.,’ Lond., series B, vol. 
cxcv, 1903. 
“Studies in Echinoidea. No. II: The Result of Crossing the 
species Echinus esculentus and Echinocardium cor- 
datuni,” ‘ Quart. Journ. Mic. Sci,,’ vol. 58, 1912. 
Mortensen. — “Die Echinodermen Larven der Plankton Expedition,” 
‘ Ergeh. Plank. Exp.,’ vol. ii, J, 1898. 
“Die Echinodermen Larven,” ‘Nordisches Plankton,’ Lief i, 1901. 
‘‘ On the Development of some British Echinoderms,” ‘ Journ. 
Mar. Biol. Assoc.,’ vol. ix, 1913. 
Muller, J. — “ Ahhandlungen iiber die Larven und die Metamorphose der 
Echinodermen,” ‘ Abh. Preuss. Akad. Wiss.,’ iii, Berlin, 1846, 
Theel, H. — “On the Development of Echinocyamus pusillus,” 
‘ Nova Acta. R. Soc. Sci.,’ Upsala, 1892. 
Ubisch, L. von. — “Die Entwicklung von Strongylocentrotus 
livid us,” ‘ Zeit. wiss. Zool.,’ vol. cvi, 1913. 
Vernon, H. M, — “ The Relations between the Hybrid and Parent Forms 
of Echinoderm Larva:,” ‘Phil. Trans. Roy. Soc.,’ Lond., series B, 
vol. cxc, 1898. 
EXPLANATION OF PLATES 83 and 34, 
lilustratiiig Prof. E. W. MacBride^s paper on The Develop- 
ment of Echinocardium cordatum. 
List of Abbreviations Employed. 
a. Larval aims. ab. calc. Calcareous centre for formation of aboral 
rod. c(h. cil. Aboral crest of cilia, ab. mes. Aboral mass of mesen- 
chyme, ab. pi. Rudiment of plate belonging to the aboral surface of 
the adult, ab. r. Aboral rod. a. d. a. Antero-dorsal arm. ad. cil. 
Adoral band of cilia, ad. sp. Adult spines. a. 1. a. Antero-lateral 
arm. a. 1. r. Antero-lateral rod. cwi. Amniotic cavity, a. m. Adult 
mouth, a.p. Apical plate of the early larva, b. r. Body -rod. calc. 
