150 DR. R. YON WILLEMOES-SUHM ON THE 
cells in the interior. On the right side the yelk gives way at the place 
where afterwards there will be a groove between the appendages : y , blasto- 
dermic cell ; x, yelk-globules. 
Fig. 8. The blastoderm has spread all over the ovum and enclosed the yelk. Reflected 
light. 
Fig. 9 a. Front view ; fig. 9 b, side view. First formation of the three pairs of 
appendages (a, b , c ). 
Fig. 10. The embryo in its thinner and enlarged (1 blastodermic) cuticle, length 0’28 
millim. : a , b , c, the three pairs of appendages ; la, labrum. 
Fig. 11. The Nauplius having just come out. Dorsal view: a, b, c, the three append- 
ages ; cp, the lateral horns ; la, labrum ; oes, oesophagus ; c, cauda ; prc, 
processus caudalis, or the spine attached to the tail’s posterior side. These 
two are invaginated and enveloped by a very thin cuticle, as also are the 
ends of the lateral horns (figs. 11 a & 11 b). Natural size : length 0*35 millim. 
Fig. 12. An adult Nauplius ( Archizoea , Dohen) seen from the side, x 12 nat. size. 
All the figures, with the exception of fig. 12, were drawn under a high power. 
(Hartnack \ or -g-.) 
PLATE 11. 
Fig. 13. Nauplius after the first moult. Drawn from specimens kept in globes as 
well as from those caught on the surface, a, b, c, the three appendages ; cp, 
cornua parietalia ; la, labrum ; oes, oesophagus ; sp, the first one of the large 
spines on the tail ; ac, the caudal spine ; x, feelers ; z, spines of the carapace. 
Natural size of this embryo : — 
Length of the whole animal .... 061 millim. 
Length of front of embryo . . . . 0T7 „ 
Length of cornua parietalia . . . . 026 „ 
Length of carapace 0T9 „ 
Length of tail ■ ... 0*42 „ 
Fig. 14. Nauplius after the second moult. From the surface of the Pacific. Letters 
the same as in the last figure, except : — cer, first formation of the ganglia ; 
coe, glandular bodies ; pr, processes of the carapace, into which the unicellular 
glands send their ducts ; ad, dorsal spine. 
PLATE 12. 
Fig. 15. Nauplius (. Archizoea , Dohrn) after the fifth moult. From the surface. The 
tail with its large dorsal spine has been bent over a little to the side to show 
the end of the intestine and the glands ; also the labrum has been turned 
over a little to show the mouth and the narrow channel by which it is in 
communication with the oesophagus. The muscles in the tail and the caudal 
and dorsal spines have grown, and, not being able to stretch out, are taking 
