301] PSEUDOPHYLLIDEA FROM FISHES—COOPER 13 



Order PSEUDOPHYLLIDEA Carus 1863, nee Luhe 1910, e. p. 



Polyzootic cestodes with mostly unarmed scolex without rostellum or pro- 

 boscis formation, excepting in the Haplobothriinae where the primary scolex 

 is provided with four protrusible proboscides resembling those of the Try- 

 panorhyncha. Usually with two weakly developed sucking grooves, which 

 in individual cases are modified by the strong development of their walls or by 

 more or less extensive fusion of their edges, so that they may appear funnel- 

 shaped or tubular, which may also unite with each other more or less com- 

 pletely to form an unpaired terminal adhesive organ, or become rudimentary 

 or entirely absent, in which latter case they are replaced by a terminal function- 

 al organ of attachment. The development of a pseudoscolex takes place occa- 

 sionally. External segmentation more or less pronounced, only seldom com- 

 pletely absent. Genitalia in each segment usually single, seldom double. 

 Their development proceeds from ahead backwards and does not continue 

 to a degeneration of the reproductive glands; but the majority of the pro- 

 glottides, being at the same stage of development, bring their sexual products 

 to maturity at the same time, so that in all of them new eggs are formed con- 

 tinuously and all the eggs of the whole animal are at the same stage of embryon- 

 ic development. A surficial opening of the uterus is always present. 



Testes numerous; vas deferens strongly coiled, without a true seminal 

 vesicle. Ovary near the posterior end of the proglottis, mostly median in 

 the case of single genitalia, seldom approaching the margin of the strobila 

 bearing the genital opening (that of the cirrus and vagina). Vitelline follicles 

 very numerous, mostly in the cortical, seldom in the medullary parenchyma. 

 Uterus a more or less winding canal, the individual coils of which converge 

 somewhat towards the centre of the proglottis to form the so-called rosette; 

 but in other forms it enlarges to form a capacious cavity, the uterus-sac, from 

 which the duct-like beginning of the uterus is sharply separated. Eggs oper- 

 culate or non-operculate, developing mostly only after being laid, but in other 

 cases within the uterus. 



The above diagnosis of the order is that of Liihe (1910:11), minus the family 

 Caryophyllaeidae and partly emended to accommodate the subfamily Haplo- 

 bothriinae, in which what is here considered to be the true (or primary) scolex 

 is deprived of bothria but provided with four eversible proboscides quite 

 comparable in structure to those of the order Trypanorhyncha. It is evident 

 that what was formerly (Cooper, 1914, 1914a) called the scolex of Haplo- 

 bothrium cannot now be considered to be a true scolex but only the foremost 

 segment of the adult or secondary strobila, which is indicated by its resem- 

 blance internally as well as externally to the segments immediately following. 

 Whether or not a pair of bothria were originally present or are present in the 

 ver\' earliest stages, whether such bothria have become modified into the pro- 

 boscides, or whether the latter have developed from four separate "accessory 



