192 CLASS v. 



of the body are simple, in the posterior part evanescent. Head sub- 

 globose, beset with simple spinules. Mouth bivalved naked. Tail 

 of male spiral, with genital spiculum elongate, simple. 



Sp. Cheiracanth. robustus DIES. Ann. des Wien. Mus. II. 1840, Tab. xv. 

 gg s> i 7 in the stomach of different species of Cat. This animal has 

 four long sacs near the oesophagus which recal the lemnisci of the Acan- 

 thocephala. According to DIESING the genus Gnathostoma OWEN, (Pro- 

 ceedings of the Zool. Society iv. 1836, pp. 123 126), a worm found in the 

 walls of the stomach of a tiger, is not distinguishable from this ; the mouth 

 however is differently described by OWEN. 



Lecanocephalus DIESING. Body anteriorly obtuse, with head 

 expanded in form of a platter, and mouth trilabiate. Simple 

 spines surrounding the body in zones. Tail of male inflected, witli 

 double spiculum. 



Sp. Lecanoc. spinulosus DIESING, Ann. des Wien. Mus. 11. Tab. xiv. figs. 

 12 20. 



Ancyracanthus DIESING. Body acuminate at both ends. Mouth 

 orbicular, armed with four spinules pinnatifid, disposed in a cross. 

 Tail of male inflected, with double spiculum. 



Sp. Ancyr. pinnatifidus DIESING, Ann. des Wien. Mus. n. Tab. iv. figs. 

 21 27 ; in the stomach and small intestine of South American tortoise. 

 Here also there are four long csecal sacs near the oesophagus, as in Ckeira- 

 canthus. 



Note. To the Nematoidea are also referred some filiform entozoa, included 

 in a vesicle. In the peritoneum of various fishes, between the coats of 

 the intestines and elsewhere a white worm of this sort, convoluted spirally, 

 is found, which LINNAEUS called Gordius marinus, EUDOLPHI Filaria 

 piscium. Comp. SIEBOLD in WIEGM. Archiv. iv. 1838, pp. 305, &c. 

 Here also belongs a microscopic worm found by OWEN in the muscles of 

 man, and called Trichina spiralis. See Transact, of the Zool. Soc. I. 4to. 

 1835, pp. 315 324, Tab. 41, figs, i 9. Is it a Nematoid in an imperfect 

 state, the rest of whose fortunes are unknown ? [This is V. SIEBOLD'S 

 opinion. The encysted Trichina is sexless and does not increase in size. 

 Sometimes the liver of different marine fishes is beset with cysts containing 

 round worms which have grown to an inch or more in length ; they have 

 been named A scar is capsularis, Filaria piscium, &c. SIEBOLD could never 

 discover in them sexual organs, but still they have so remarkable a 

 resemblance to Ascaris osculata, spiculigera, angidata, &c., worms with 

 developed sexual organs which live in the intestinal canal of the Seal, the 

 Cormorant, the Diver, the Gull, and predaceous fishes, that they may be 

 suspected to be related to them. SIEBOLD believes that the encysted sexless 

 worms only attain their perfect development in the intestine of the verte- 

 brates which have swallowed their temporary hosts. VON SIEBOLD Band 

 u. Blasen-wiirm. s. 32, 33. 



