CoTTRELi.. — Styelii cnci'uleii {Quo[/ (ind ( !(ii iiun-d) 



169 



test, giving it a green appearance ; Quoy and Gaimard'.s figure siiows this 

 green colour near the base of the specimen figured. The test is strong and 

 substantial, of a leathery nature, and frequently nu>re or less cartilaginous. 

 It is often about ^in. in thickness. The blue colour extends almost 

 through the thickness of the test. 



The iiiaiifle is well developed ; it is not attached firmly to the test except 

 at the siphons, and is thick, opaque, and of a yellow colour. The muscles 

 are not grouped into strong bands, but form a close network of small bundles. 

 Some larger bands can be seen on the inner side of the mantle. 



The hniiichidl sac (fig. 1) has four well-marked folds on each side ; the two 

 ventral folds are sm,aller than the others. About 10 internal longtitudinal 



yuiiuvi^i^m' 



Fig. 1. — Part of the branchial sac of StyeJa coeruh't, from an interspace; x 25. 



bars occur on a fold, and usually 3, sometimes 4, in the interspace ; the bars 

 are wide and ribbon-like. The following table, compiled from the examina- 

 tion of seven typical specimens, shows the variation of the number of these 

 bars on the folds of each side ; the folds are numbered from dorsal to ventral. 



