94 THE VICTORIAN NATURALIST. 



running down from it. At the bottom of the bladder are 

 several appendages, of varied size and form ; some short, with 

 suckers attached on each side; while others are like long 

 tentacula, which can be extended to an immense length, or 

 contracted at pleasure. One which I captured had its tentacula 

 extended to a depth of at least twelve feet, which I ascertained 

 by thrusting a very long oar down to its full length, and finding 

 portions of the tentacula attached to the extremity of the 

 blade. Woe to the unfortunate inexperienced fisherman who 

 allows any portion of the tentacula to touch his skin, the 

 sensation being similar to that produced by a powerful stinging 

 nettle, with dull pain in the limb for a considerable time. The 

 physalia lives on small fish, shells, and other victims which 

 happen to come under the influence of its prehensile tentacula, 

 which instant.y paralyse and draw up to the mouth and stomach 

 its unhappy prey. 



We also find various forms of porpitae, which are simple disc- 

 shaped mollusks, with no apparent power of locomotion. 

 Their food — seized by small tentacula in the same way as the 

 physalia — consists of small shells whicli come within their 

 reach. One variety, the " velella," has a sort of membrane 

 placed obliquely across the upper surface, which acts as a sail, 

 and drifts its owner in whatever way the wind is blowing. I 

 have frequently captured "porpitae" and " velellse " with 

 janthina and other shells nearly as large as themselves, which 

 they were consuming with avidity. 



Another interesting family of shell-less mollusks frequently 

 taken in the net is that of the "Nudibranchiata" species of sea- 

 slug. These have no pulmonary chamber, but have the organs 

 of respiration situated in the branchiae on their upper surface. 

 Among these I have captured " Doris cornuta," or the horned 

 doris, and " Glaucus Atlanticus," or sea-lizard, which is a very 

 extraordinarily beautiful creature when first caught, the upper 

 surface being marked with deep blue and purple, having black 

 lines running down each side of the body, while the lower side 

 is of a pure silvery white. They float in a quiescent state on 

 the ocean, unless touched, when they fling themselves about in 

 a very excited way. They live on " porpitae," " velella^," and 

 similar mollusks, and their appetite appears to be aldermanic. 



Of another order, " Nucleobranchiata," which consist of 

 mollusks with large bodies and very small shells, I may 

 mention the Carinaria, of which the body is transparent and 

 dotted with elongated points, the tail being pointed with a sort 

 of fin, which acts as a rudder, and on the top of the animal 

 the foot is situated. 



Another peculiar creature is the "Clio borealis," or whale 

 food, on which that huge animal largely subsists. 



Before dealing with mollusks which have a shell covering, I 



