PARASITES. 249 



glass, on November 25tb, I next clay found many embryos, eacb in its 

 amnion or involucrum, quiescent. Intermingled with these were nume- 

 rous ^ybite specks, in active motion, which, under the microscoiDe, proved 

 young Caligi, very minute, provided with six limbs, nor shewing any 

 resemblance whatever to the parent. 



Nothing could be more transparent than the amnion involving the 

 embryos, some of which soon burst their prison. — Fig. 6, enlarged ; young, 

 fig. 7, magnified. 



Now, the illusion representing the cylindrical appendages as in- 

 dented, was dispelled ; for the supposeil circles, forming so many annula- 

 tions, had originated from the embryos, in their integuments, being piled 

 like so many j^ieces in a rouleau of coinage, horizontally aljove each other. 



Among a number of the adult Califji examined on November 30th, 

 many specimens wanted the ovarian cylinders, while the discharge of 

 embryos in their integuments continued from those that had them. 



At least twenty specimens were found among Caligi collected on 

 the 5th ; all wanting the tubes. 



At this time they were infested by the Udonclla. 



From the form of the Caligns, displayed on bursting its integument, 

 compared with that of the adult, the animal undergoes an evident meta- 

 morphosis in its course to maturity. 



The surface of the shell is frequentlj' speckled red, and many be- 

 come ruddy or purple, as the animal dies. Some of the young, on escap- 

 ing from the amnion, seem to be speckled. 



Several facts regarding these minute animals are unintelligible, and 

 others very indistinctly understood. Indeed, I am at a loss to compre- 

 hend the real nature of almost the whole external objects affixed to the 

 figures represented in the plate. 



A minute zoophyte, fig. 10, had found a nidus among them. 



§ 2. Caligus salmonis. — Plate LXVII. fig. 1 . 



As the preceding parasite infests the Cod, so does the present subject 

 infest the Salmon. To free itself of this obnoxious enemy, the Salmon is 

 said to quit the sea and ascend rivers ; but whether truly so, I cannot cer- 



2i 



