^115. 



THE IIELMINTHES. 



123 



Taenia, it is a reservoir, composed of numerous ramified coeca, and inti- 

 mately blended with the parenchyma of the body.*-''' The vagina is a nar- 

 row, muscular canal, which usually opens close to the penis by a special 

 orifice (Vulva), or by a common genital opening [Porus genitalis). 



It is diSicult to decide whether the testicles, which always form the 

 middle layer of the body, consist of a collection of inter-opening caeca, or 

 of a single spirally-rolled tube. Thecirrhus-sac with the Vas deferens open- 

 ing at its bottom, is always very distinct. As in the Trematodes, it has a 

 Vesicula seminalis, with a Ductus ejaculatorius and a muscular penis.*-''* 

 The contents of the different canals, the seminal vesicle and the ejacula- 

 tory duct, are always very active, filiform spermatic particles.'-''* The 

 genital openings are upon the middle of the ventral surface, or on the 

 lateral borders of the body ; but in those species where the sexual openings 

 are separate, they are lateral for the male, and ventral for the female.*-*' 



The eggs of the Cestodes, situated like those of the Trematodes in a 

 spiral, pouch-like uterus, have also a similar structure. Their simple, oval, 

 brownish-yellow envelope, has also, sometimes, an operculum. The eggs 

 of Taenia have a very different structure ; the envelope is colorless, and 

 of a very variable, and sometimes quite remarkable form.*-''^' 



23 With most Taeniae the borders of the cellular 

 uterus are very difficult to distinguish. But its 

 lateral caeca with Taenia ocellata, and its arbo- 

 rescent divisions with Taenia •solium., are very 

 easily seen ; see Delle Chiaje, Compendio di 

 Ehnintografia umana, Tav. HI. flgr. 10. 



24 The cirrhas-sac is either short and pyriform, 

 or very long. W'ith very many Taeniae, as with 

 Taenia amphitrica, lanceolata, multistriata, 

 scotecina, and seti^era, the penis has numerous 

 small spines pointing backwards ; see Dujardin, 

 Hist. d. Helm. PI. IX.-XI. That of Taenia 

 infundibuliformis is surrounded with very large 

 bristles ; and according to Dujardin (loc. cit. PI. 

 IX. B. 210) this is also true with Taenia sinuosa. 



25 By very slight pressure, the spermatic parti- 

 cles contained in the Vesicula seminalis of the 

 cirrhus-sac are pressed out through the penis ; 

 this is so with Bothriocephalus punctatu.i, latus. 

 Taenia cucuTnerina, planiceps (from the intes- 

 tine of Hirundo urliica), injlata , pectinata, ser- 

 pentulus, and villosus. As with the Trematodes, 

 the spermatic particles here cease to move when 

 put in water, and are twisted into loops.* 



2ti With Ligula, Bothriocephalus nodosus, 

 latus, claviceps, ditremus, punctatus, and te- 

 trapterus, the two genital openings are situated 

 on each side of the ventral surface, while the penis 

 protrudes from a special opening directly in front 

 of the vulva; set Mehlis in Isis,1831, Taf. I. fig. 

 1, 2, and Eschricht, loc. cit. Tab. I. fig. 5. 



With Bothriocephalus punctatus, there are 

 two ])airs of these openings upon each segment, 

 one under the other, but in Bothriocephalus te- 

 trapterus, these are side by side. With Triaeno- 

 phorus, nod«/osu«, and Taenia ocellata, the vulva 

 is upon the ventral surface, and the jiltus upon 

 the lateral border. With Bothriocephalus fra- 



gilis, proboscideus, rugosus, and with most Tae- 

 niae, the cirrhus-sac and the vagina open by a 

 common genital orifice upon the lateral border, 

 and usually through a papilla. With Taenia 

 cucumerina, and bifaria, mihi (from the intestine 

 of ^nas leucophthalmus), I have found an orifice 

 of this kind upon the two lateral borders of each 

 segraajit, and behind which were the genital or- 

 gansT 



27 Although I have not seen either the germina- 

 tive vesicle or dot in the eggs of the Cestodes, 

 probably from their delicacy, yet I do not for a 

 moment doubt their presence there, since Kolliker 

 (Muller's Arch. 1843, p. 92, Taf. VII. fig. 44) has 

 seen them in the eggs of a Bothriocephalus. 

 Many species of this genus produce oval eggs 

 which have a simple brown envelope. Of an oval 

 form, but colorless, are those of Carijophyllaeus, 

 Ligula, Triaenophorus, Taenia literata, and 

 scolecina. Those of Taenia amphitricha, bifa- 

 ria, macrorhyncha, serpentulus, and serrata, are 

 round, and have two colorless envelopes ; this is true 

 also of the oval eggs of Taenia angulata, viltosa, 

 ifC. There are three of these envelopes with the 

 round or oval eggs of Bothriocephalus infundibul- 

 iformis, proboscideus. Taenia porosa, lanceo- 

 lata, ocellata, setigera, and solium. With Tae- 

 nia infundibuliformis, and planiceps, each ex- 

 tremity of the envelope is lengthened into a long 

 and delicate appendage. Two similar but fibril- 

 lated appendages exist upon those of Taenia 

 variabilis. With Taenia cyathiformis, the ex- 

 ternal pyriform envelope of the eggs has, at its 

 attenuated extremity, two round, bladder-like !cp- 

 pendages. Dujardin (Hist. d. Helm. PI. IX.- 

 XII.) and I (Burdach's Physiol. 1837, II. p. 201) 

 liave seen many other forms with the eggs of 

 Taenia. The round and doubly-enveloped eggs 



* [§ 115, note 25.] I have observed the de- 

 velopment of the spermatic particles with Taenia. 

 They are developed in special cells, and before 

 they have escaped, are therein coiled up resembling 

 those of the coleopterous insects. They are simply 

 filiform. — Ed. 



t [ § 115, note 26.] The Cestodes have been the 

 objects of much careful study during the last few 



years, by B/anchard (.^.nn. d. Sc. Nat. X. 1848, 

 p. 321) and Van Beneden (Mem. Acad. Belgique, 

 1850, X.XV.) and the sexual parts pretty clearly 

 made out. They both agree that, internally, the 

 male and female organs are wholly distinct, and 

 therefore that impregnation of the ova must be by 

 self-copulation. — Ej). 



