22 Prof. J. C. Schiodte on the Structure of 



responds with the far greater development of the hooked limbs 

 in that genus, to which we shall allude further on. 



The mandibular jpaljpi [m^ fig. 6 a), on the contrary, enter 

 into far closer connexion with the mouth-tube in Cymothoa 

 than in ^ga. Instead of being slender and furnished with a 

 brush of bristles and a comb of spines as in j:Ega^ they are 

 short, thick, and conic, and they are inserted on the stem in 

 such a manner that they become directed straight forward. 

 They are accordingly applied to a different purpose, namely 

 to the support of the mouth-tube, round which they lie closely, 

 meeting in front of it and embracing it between them. In 

 Anilocra (fig. 5) this destination of the mandibular palpi is 

 still more apparent in their form, the joints of the palpi being 

 so accurately fitted to the space between the antennse and 

 the labrum that they sm-round the mouth-tube as a kind of 

 padding. 



Excepting that the sawing-styles formed by iho, Jirst pair of 

 maxillce (fig. 6 h) are less powerfully armed than in ^ga^ the 

 difference in the inner machinery is confined to the structm-e 

 of the mandibular lobes {m, fig. 6 b), which are thin, triangular, 

 pointed lobules, with a sharp inner edge, and are doubtless used 

 not merely for stinging, but also for the pm-pose of clipping, 

 as they are capable of being crossed like the blades of a pair of 

 scissors. 



The formula for Cymothoa will consequently be the follow- 

 ing :— 



Cymothoa. 

 Os haustellatum. 



Haustellum adversum clypeo labroque, aversum in foemina 



malis posterioribus, in mare mahs posterioribus palpisque 



pedum maxillarium confectura, malas mandibulares punc- 



torias maxillaresque priores rasorias involvens. 



Clyjpeus fornicatus, pendulus. 



Labrum amplum, semicirculatum, pendulum, fornicatum, mar- 



gine minute verruculoso. 

 Mandibulm stipite quadrato, fixo, apice palpigero, mala inte- 

 riore nulla. Mala exterior sub labrum oblique inflexa, 

 mobilis, in orificium haustelli deorsum eminens, triangula, 

 compressa, acuminata, cultriformis. Palpus labrum utrin- 

 que amplectens, triarticulatus, conicus, nudus ; articulis 

 sensim decrescentibus. 

 MaxUlce priores stiliformes, mala interiore et palpo nullis. 

 Mala exterior stipiti contigua, in orificium haustelli deor- 

 sum eminens, fasciculo armata terminali hamorum raso- 



