ON THE ANGUILLULID^. Ill 



genus Anguilhila, he has now, in his more recent ' E-evision der Nematoden,' transferred 

 to the genus Isacis of Lespes ; whilst he includes, as subsections of the former genus, 

 certain other of these parasitic forms, mostly discovered by Dr. Leidy, of Philadelphia, 

 and placed by him, rightly enough, in distinct genera — Streptostoma, Thelastoma, and 

 Hystrignatlms. 



For many of the descriptions and references concerning old species placed in this and 

 other genera I have freely availed myself of Diesing's admirable work. 



1. A. ACETi, Ehrenberg. (PI. X. figs. 59a-69c.) 



Borellus, Obs. Microscop. Centur. 7» 1656. 



Power, Microsc. Obs. 38. 



Hook, Microsc. i. 2, tab. i. 



Joblot, Obs. Micr. i. 2, tab. i. 



Leeuwenhoek, Phil. Trans. 1676, p. 656. 



Cellius, apud Bakerum, ii. 250 (vivipara). 



Backer, Micr. tab. x. 8, 9 ; Micr. Expl. 81, tab. v. 10. 



Frankische Samml. iv. 277? figs- g-o. 



Goeze, Naturf. i. St. 1-53, et xviii. St. 38, tab. iii. 12-19. — Idem in Bonnet's Organis. Korp. 59. 



Spallanzani, Opus. Phys. i. 83. 



Rozier, Anguille du Viiiaigre, Obs. 1775, Mars, tab. i. fig. 5 ; 1776, Janv., 51, et Mars, 382. 

 Essig-Aelchen, Martini, Allgem. Gesch. d. Nat. i. 412; Beschaft. Berlin. Gesellsch. i. 342. 

 Chaos redivivmn, Linne, Syst. Nat. 1326 (aceti). 



Vibrio anguillula, a. Anguillula aceti, Miiller, Anim. Infus. 63, tab. ix. 1-11. — Idem, in Naturf. xix. St. 162. 

 Vibrio aceti, Bory, in Encycl. Meth. 1824, p. 788, tab. iv. 16. — Duges, in Ann. des Sc. Nat.ix. 225, tab. xlvii. 

 2, 19, 32 5 , et xlviii. 44-50 cJ , 51 (in copula).— De Blainville, in Diet, des Sc. Nat. Ivii. 573 et Iviii. 70. 

 Rhubditis aceti, Dujardin, Hist. Nat. des Helminthes, 242. 



Czernay, Monogr. d. Essig'alch. mit kol. Kpft. Moskau, 1849. — Idem, Bullet, de Moscou, xxii. (1849) 

 232-256, tab. vi. (cum anatom. et de evolut.). 

 Anguillula aceti, Ehrenberg, Infusionsth. 82. 



Leidy, in Proc. Acad. Philad. viii. (1856) 48. 



Hogg, Pop. Sc. Review, Jan. 1863, p. 216, pi. x. 



Diesing, Syst. Hebninth. ii. p. 128 ; et Sitzungsb. ais. Akad., Bd. xlii.. No. 28, p. 62?. 



Female (size very variable). Length -^", breadth 5-53^". 



External Characters. — Body white, much obscured by colourless granules within 

 integument ; long and narrow, tapering very much posteriorly, and terminating in a long 

 pointed extremity. Head rounded, unarmed. Integument thin, showing no striae. 



Pharyngeal cavity very minute, cup-shaped. (Esophagus ^th of total length, having a 

 rounded swelling at termination, containing valvular apparatus. Intestine covered with 

 coarse colourless granules ; no sort of tessellation. Anus -^q" from posterior extremity. 

 Vulva somewhat posterior to middle of body. Uterus unsymmetrical. Small fioatmg 

 gland-cells numerous in cavity of body. 



Male. Length -^", breadth 3^". 



(Esophagus yth of total length. Anus xW froi^i posterior extremity. Spicules narrow, 

 having a double curve, 7x4" long. Accessory piece about ^rd as long as spicules, rather 

 thick externally, but expanding inwards into a thinner fan-shaped portion. 



