484 ENTOZOA. 



[Class Annulata. 



Order Errantia,] 



The Sea Mouse '[Aphrodite aculeata, Linn.]. 



This animal, according to its parts, and being similar to a caterpillar, 

 comes nearest to an insect in the first state. Its external hair 1 is in 

 some degree similar: its stomach 2 and gut 3 , also its pancreas or liver 4 , 

 are a good deal like the same [in insects]. The nerves 5 are similar, as 

 also the circulation 6 ; but I believe their respiration 7 is not similar. 



[Class Entozoa.] 



Of Worms in the Whale-Tribe [Echinorhynckus porrigens, Bud., 

 and Echinorhynckus glandiceps, Ovv.] . 



Animals of every species have probably smaller animals living upon 

 them, which are either situated upon the external surface of the body, 

 or in some of the internal canals ; and many species, besides the whale, 

 afford a nidus, or a simple attachment, to such. The animals which 

 live upon the external surface of others are commonly insects, and 

 constitute, I believe, one order of that class. Those found in the internal 

 canals are called ' worms ' [Entozoa], but differ very much among them- 

 selves. Those which are contained in a nidus with an external opening, 

 formed on living animals, are larvae of winged insects [CEstri], and those 

 which are simply attached are generally marine, and adhere to the 

 larger fishes [Epizoa]. 



Perhaps every species of animal has a species of insect peculiar to it ; 

 as in the instances where the body affords a nidus to such. The same 

 observation may in some degree hold true with respect to worms ; and 

 although many which are found in different animals appear to be similar, 

 yet there is probably some specific difference 8 . 



These observations, although in general true, are not, however, with- 

 out exceptions ; for I have found the same kind of worm in the intestines 

 of the whale 9 as in the eider-duck 10 , and we know that the intestines 



i [Hunt. Prep. Phys. Series, No. 2068.] 2 [lb. No. 465.] 



3 [lb. No. 595.] 4 [lb. Nos. 782, 783.] 



5 [lb. No. 1297.] 6 [lb. No. 849.] 



7 [lb. Nos. 985 — 988. See also the beautiful figure of the vascular and respiratory 



system of Amjihinome capillata, from a Hunterian drawing, in the Physiological 



Catalogue, 4to, vol. ii. pi. 14. fig. 10.] 



s [This idea has since been verified, chiefly by the labours of Eudolphi, in his 



'Historia' and 'Synopsis Entozoorum.'] 



9 [Echinorhynchiis glandiceps, Hunt. Preps. Phys. Series, Nos. 295, 415, 2323.] 



10 [Echinorhynchus lendix, Phipps ; Ech. filicollis and Ech. versicolor, Rud. This, 

 though similar to. is distinct from, the Ech, glandiceps of the piked-whale. It is 



