LIFE HISTORY OF ANAPHIA PETIOLATA. 5 
Or 
dactylus pygmeus (Hoek, 1881; Hodge, 1864). By comparing these 
young forms with older undoubted specimens of Anaphia petiolata 
(Kroyer), they correspond exactly with the exception of the length of 
the cephalic segment, which grows with the animal just as Canon Norman 
suggests (1894). The growth, however, appears to take place after the 
ae 
“s 
= 
A 
a ea Les 
aX aD gee Gi 
Cy a 
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Fic. 3.—Diagram to show growth of cephalic segment. A. Length 0°70 mm., young 
Anaphia petiolata directly after emergence from the last larval skin ; 
B. Length 0:90 mm., later stage; C. Length 1:04 mm., later stage in which 
all legs are developed; D. Length 1°56 mm., nearly full grown. 
ee 
eae 
. 
A 
a 
moult in which the walking legs are complete, that is to say when the 
body and legs are fully formed, for a series of measurements show that 
there is very little difference in the length of the cephalic segment of the 
young form after it has sloughed its last larval skin and the young form 
with completely formed legs (see Fig. 3). The increase in length takes 
place afterwards. 
LITERATURE. 
1915. Caztman, W. T.—Pycnogonida. British Antarctic (“ Terra Nova ”) 
Expedition. 1910. 
1913. Docren, V.—Embryologische Studien an Pantopoden. Zeitschrift 
fiir Wissenschaftliche Zoologie, Bd. 107, pp. 575-741. 
1864. Hoper, G.—List of the British Pycnogonoidea with Descriptions of 
Several New Species. Annals and Magazine of Natural History. 
Feb., 1864. 
188]. Hork, P. P. C—Nouvelles Etudes sur les Pyenogonides. Archives de 
Zoologie Expérimentale et Générale, pp. 445-542. 
1906. Merron, H.—Kine auf Tethys leporina parasitisch lebende Pantopo- 
denlarve (Nymphon parasiticum, n. sp.). Mittheilungen aus der 
Zoologischen Station zu Neapel, Bd. 18, pp. 136-41. 
