The Life History of Anoplodactylus 
Erectus Cole 
WILLIAM A. HILTON 
As an introduction to the statement of the life history of this 
species it may be worth while to briefly review something of the 
literature on the subject and follow this with all that is known of 
our Californian or Laguna Beach forms. 
The fact that the males carry the eggs after laying was first 
determined by Cavanna in 1877. The eggs are large or smaller 
according to the yolk present. In Phowxichilidium and Tanystylum 
studied by Morgan, the eggs are .05 mm., in Palene, .25 mm. In 
certain species of Nymphon they have been described as large as 
.5 to .7 mm. in diamater, Dohrn, ’81. The egg masses are one or 
more for each leg. In Palene there are only two eggs in each group, 
but according to Dohrn there may be a hundred or more in each 
bunch. In some cases both legs hold a single mass. Segmentation 
is complete and equal in the smaller eggs, unequal in the larger. 
The best account of the later development is given by Meisenheimer 
for dmmothea in 1902. A typical gastrula is formed by an in- 
growth of cells from the uniform almost solid previous stage. This 
gastrula however has no cavity, but later it forms into midgut and 
dorsal and lateral parts, the sources of the heart, muscles and con- 
nective tissues. Later there is a longitudinal germ band about the 
yolk and in this, paired thickenings appear which represent the 
cerebral and subesophageal ganglia, lateral thickenings mark the 
point of origin of the appendages. The chelifori are the first to 
appear. In Palene (Morgan) the fourth leg is next, then the fifth 
and sixth. The third and seventh come just before hatching. 
Palene and some other forms such as some species of Nymphon 
have in the larva all of the appendages of the adult, but most free 
larve are provided with three pairs of appendages. Such are called 
protonymphon stages. In various species these appendages differ 
somewhat, but in practically all, the body is similar at first. The 
body during early larval stages is roughly circular in outline, the 
