of the Fishery Board for Scotland. 



161 



IT.-IV. In the remaining Zoea stages the eyes are quite free from 

 the carapace, and have very short stalks. Fig. 157 represents the eye 

 of the IV. Zoea. 



Megalops (Figs. 152 and 153). The eyes have very long thick 

 stalks, through which they are projected laterally well out beyond the 

 edge of the orbit. 



In succeeding stagtis, development, so far as concerns the eye, consists 

 in its gradual reduction in size, and in its shifting from a lateral to an 

 antero-posterior position, 



1 (Fig. 167). The eyes are much reduced in comparative size. 



2, 3, and 4 (Figs. 173, 170, and 171). The eyes are now bending 

 forward. The eye is, however, too large to be contained within the 

 orbit. 



Crab 5-5 mm. across (Fig. 172). The eye can now lie down in the 

 orbit. 



Adult (Fig. 168). The narrowing of the frontal region has brought 

 the eyes closer together. The bend in the eye stalk was first noticed in 

 the third and fourth young stages. The eyes are now very small. 



The eye has simply taken part in the general alteration in the anterior 

 half of the carapace. 



Carapace, Plates xii. and xiii. 



I., II., III. (Figs. 159, 148, and 147). The carapace of the Zoea 

 except in possessing the dorsal spine, similar to that of a Macrouran. 

 It is prolonged in front into the long, almost straight, rostral spine ; and 

 from the middle of the dorsum, immediately over the heart, rises the 

 curved dorsal spine. In these stages no hairs were found on the edge 

 of the carapace, 



lY, (Fig. 146). The carapace is as in previous stages, except that 

 there is now a row of small ciliated hairs attached on the inner side 

 of the margin. 



Megalops (Fig, 153). — The dorsal spine has disappeared, and the 

 rostral spine is reduced to small dimensions. Over the surface of the 

 carapace, and round the hind lateral border, there are distributed 

 small plain hairs. The hairs are symmetrically arranged as shown in 

 the sketch. The frontal region is broad, and the eyes are in conse- 

 quence widely separate. It has no lateral teeth. 



The carapace is longer than it is broad. 



1. (Fig, l66). The four lateral teeth appear in this stage, and of 

 these, two are more prominent than the others. The corner of the orbit 

 might be regarded as a tooth, but it is not properly so designated. The 

 general form of the carapace is nearly circular. It is just about as 

 broad as it is long. The broad frontal region is noteworthy. The 

 rostral spine has disappeared, and the frontal area shows a trilobed 

 waving. 



The carapace is covered on its dorsum with the minute "needle- 

 point" cilia, and it is supplied with ciliated and plain hairs. The 

 ciliated hairs which are located on or near the edges are similar to the 

 ciliated hairs found on the dorsum of the abdomen (Fig. 128). The 

 plain hairs are scattered over the dorsal surface of the carapace. The 

 minute cilia are very thickly distributed : in the drawing their size is 

 exaggerated. 



" From the first to the sixth young stage the carapace assumes its 

 normal shape by a gradual increase in its width compared to its lengt^h. 

 With each successive moult the lateral toothed margins are pushed 

 more forward and the teeth become more prominent." (Brook.*) 



* Op. 



L 



