82 The Sunfish as a Host. 



at each extremity, one very small ; the other, through which it 

 is intended the animal's body should protrude, is propor- 

 tionately larger; the head in the middle of the body is surrounded 

 by gills ; this mollusc is a sand-borer, and feeds on minute 

 marine animals. Almost hidden from our view is a small 

 crustacean belonging to the sessile-eyed division of the family ; 

 watch how it scuttles along on its side when it reaches its native 

 element, using its swimming feet so constantly and so rapidly, 

 as to suggest the idea of their being worked by a small private 

 steam-engine ; if you examine the antenna? of this creature, you 

 will see two small secondary feelers sprouting from the upper 

 pair, the lower pair having no such appendages ; glance at that 

 broad hand, with its finger so admirably adapted for nipping, 

 andviewthestructureof the swimming plates andtail so delicately 

 fringed with ciliae, that is a Gammarus, 0. sabini. Near him 

 lies Galathea squamifera, a stalk-eyed crustacean, with pointed 

 notched rostrum, and long fore feet, its abdomen and swimming 

 tail, neatly tucked away out of sight, completely concealing 

 from our view the spawn which would soon form Zoece, and 

 ultimately crabs. 



And now, our jars being tolerably well filled, we turn home- 

 wards, rather tired, we must confess, but anticipating with no 

 little eagerness the work that remains for us on our arrival 

 there. Many a day may be pleasantly and usefully employed 

 in examining, classifying, and identifying our specimens, and 

 dissecting those whose organizations we desire to study more 

 carefully. 



THE SUNFISH AS A HOST. 



EY T. SPENCER COBBOLD, M.D., E.L.S. 



Lecturer on Comparative Anatomy, Zoology, and Botany, at the Middlesex 

 Hospital Medical College. 



Some credit is due to those of our continental brethren who . 

 have devised a set of simple terms calculated to express the 

 relations subsisting between different forms of animal life, both 

 as regards the species themselves and the various phases of 

 being known to occur in one and the same individual. The 

 Danish naturalist Steenstrup first suggested the convenient 

 titles of " nurse," " grandnurse," and so forth, in reference to 

 " parents " producing non-sexual broods of larval flukes by the 

 now well understood process of internal budding ,• and, in like 

 manner, Yon Siebold, and other German parasitologists, 

 fittingly applied the term " host " to any animal actually 

 infested with, or liable to be attacked by parasites, because it 

 thus, as it were, entertains within its own body the presence of 



