PARASITES. 251 



LERN.EA.— Plate LXVII. 



. The preceding animals are not the only instruments of torment 

 tolerated by Nature^ for the annoyance and destruction of living crea- 

 tures. There are other still more terrible and moi^e irresistible enemies 

 preying upon them, against which they do not seem to have any possible 

 means of defending themselves : for they attack different parts of the 

 body, where they are quite inaccessible to any organs of the sufferer. 



LERNyEA BRANCIIIALLS. Plate LXVII. 



This is a parasite of the most irresistible and destructive kind by 

 which any living being can be infested, and it assumes a position where 

 it is not only safe from all endeavours to shake it off, but it can scarcely 

 be dislodged by means of sharp instruments, when the fleshy part to which 

 it adheres is separated. — Plate LX\^I. figs. 2, 3, 4, 5. Its singular shape 

 precludes the powers of description ; it can be understood best only 

 from inspection of the original, and next from the figures here presented, 

 especially Plate LXVII. fig. 2, which slightly exceeds the natural size. 



The whole exterior is of a hard, horny substance ; but, in fact, what- 

 ever be the substance, it resolves into a strong vascular body comprising 

 the LerncBa, which is continually replenished with the blood of its victim. 



From an enlargement of the upper extremity, three organs issue, 

 which are provided with subordinate cruciform or branching parts, 

 fig. 2, a, inserted in the fleshy parts of the Cod, or other fish, about the 

 gills, the rest of the body substituted for the intestinal parts of other 

 parasites, being a strong and elastic tubular skin or integument. 



Capacious ovarian tubes, c, are connected with the under part of the 

 animal ; but I have not been sensible that they were occupied by spawn 

 during any periods of my inspection. 



The whole is of a hard horny, almost shelly substance, but the 

 three organs of fixture obviously belonging to the highest portion, the 

 remainder is merely to be compared to a hollow intestine. 



We cannot discover any motion of the animal, or how the head, 



