OF SOME POET JACKSON SHAEKS. 327 



seaweed. In deep water they are freer from the violent dis- 

 turbances, tending to detach them, to which the eggs of the 

 more common species are subject. 



The egg-cases of both species have the following points in 

 common: — All parts are composed of a flexible horn-like sub- 

 stance of brown colour. The body consists of a chamber shaped 

 like a pear ; the coronal portion is compressed into a cervix 

 through which the young Shark eventually escapes. From each 

 side of this cervix, and integrally connected with it, arises a 

 ribbon exactly resembling a strip of kelp. These ribbons are 

 attached basally, their free edges turned towards the cervix 

 and deflected considerably from the body. They pass round 

 alternately and obliquely, and form the thread of a right-handed 

 double screw, together making five or six turns to the base. 

 These ribbons originate about half the width they quickly 

 attain, and continue their course of even breadth, again narrow- 

 ing on approaching the base. 



The interior, as shown by a section, is wide and capacious ; 

 the fissure does not proceed to the base as is generally portrayed, 

 but terminates some distance short of it ; the inside is marked 

 with oblique striae corresponding with the direction of the spirals, 

 and resembling the lines inside a vessel turned upon a potter's 

 wheel. 



The principal diff'erences between the egg-cases of the two 

 species may be thus recounted : — 



C. Philippi, pi. XII. figs. 1 & 2. — Of larger size ; about six 

 inches in length. The spirals are very broad and, in part, hide 

 the body when viewed laterally ; at the base they narrow quickly 

 and terminate bluntly, and are not produced into tendrils. 

 Beach-worn examples generally have the terminations more or 

 less frayed. 



C. GALEATUs, PI. XII. fig. 3. — Of smaller size ; aboub four 

 inches and a half in length. The spirals are not very broad, and 

 in no part hide the body completely ; basally they become narrow 

 and are produced into long flattened tendrils. In the most perfect 

 specimen examined each tendril is ninety inches in length, and 

 tapers to the slenderest thread, becoming tangled and knotted 

 like a skein of silk. They are, however, very tough, and may be 

 unravelled without fear of breaking. One of the tendrils ter- 

 minates in a thickened tag (shown in the figure), which, although 



