THE DEVELOPMENT OF THE SQUID. 379 



features which are observed in all the specimens, and 

 which seem to be constant. 



The first which make their appearance are dark brown 

 in color, and are placed in a ring of six or seven, (Fig. 

 202), around the edge of the mantle on the posterior 

 surface. They are a little smaller, and somewhat more 

 excitable than those which appear subsequently, and 

 they can be readily recognized in the later stages shown 

 in Figs. 201 and 202. They are soon followed by 

 larger spots of the same dark brown color, scattered 

 irregularly over the posterior surface of the mantle (Fig. 

 202). 



The next spots to appear are upon the arms, and are 

 also dark brown. At first there are two upon the first or 

 siphonal pair of arms, and three upon the second pair 

 (Fig. 199). A fourth soon appears upon the second 

 arm, and these four remain conspicuous until quite a 

 late stage of development (Fig. 202). Three large 

 brown spots now appear upon the posterior surface of 

 the head (Fig. 199), and they are soon followed by 

 others. 



A second set of spots, more deep-seated and of a bright 

 orange color, soon make their appearances, and are much 

 more constant in position than the brown ones. The first 

 pair which appear are just in front of, or ventral to the 

 eves. They are soon followed by a single one on the 

 middle line of the head, at the bases of the first pair of 

 arms, and another single one on the middle line of the 

 edge of the mantle. About the same time a pair appear 

 dorsally to the eyes, and another pair on the edge of the 

 mantle, near the sides. 



Four small orange spots next appear upon the second 

 pair of arms (Fig. 202, a"), alternating with the four 



