uros s lines. Thi s rigure which alsø forms the 

 "borders o.f the weakly arched hack receives itø ex- 

 planation in the slowness of development* 



Thi s Pennella species is found huried at very 

 different depths in the Chironectes "body; sometiiaes 

 the swollen portion of the loody projects alniost its 

 entire length from the fish's slcis; sometimes it- is 

 entirely huried in the fish as far "back as the plu- 

 mules on the alodomen; or again the skin may project 

 in a ridge over it. We have no other explanation 

 to offer of thi s variation in the hurying except that 

 the parasi te' s darlcer or lighter color and the hard- 

 ness of the skin have regulatéd themselves accordingl 



From the same region of the Atlantic (29 

 N.L. & 78 W.L.)we have also found on a Diodon sexmac- 

 ulatus a young Pennella which iDy direct comparison 

 with the same development stage of the parasite of 

 Chironectes we have not loeen atole to distinguish 

 from P.sagitta. On the contrary we may assume 

 that the P.hrachiata from Manilla,t>riefly descriloed 

 Tay Blainvilli( 1822 ) and figured,will prove to be 

 different on the ftasis of its size, and will take the 

 place in the Indian Ocean that P.sagitta does in the 

 Atlantic. The question remains as to "whether 

 thi s Tndian Ocean species shall have the Linnaean 

 name,for thi s rnight naturally happen i.f we admitted 



