purpose when cocriporetivoly few cestodes had been described and there

wee not stiffielmt evidence to chow that the size end form of the hooks of the worms wore cherectere of high diagnostic value*

Our present, folrly comprehensivo knowledge of, at least# the fmro common tepo^wrm pareeites of the vettebratoe makes It possible

to correleto e larval armed ceetodo yylth its adult form from ecological and anatomical data* There is no need to carry out expérimental

infestations which# although desirable as confirmatory evldonco# eliculd net bo stipulated os a mcocsary condition for attributing

to the larval form the name of the adult* To ineist on this condition is to retreat towards the position in which parasitologists %vorked before it was roslised that the ’cystic cestodes* found In inverte* brates were in fact the larval stages of the tapowoms found In vertebrates* The taxonomies and systmatics of the Costoda are complicated enough without the larval forms being given names which bear no relationship to the names of the adults* as has been done

In the past* This practice has been adhered to even up to the present day and no real attempt has been made to name the larval cestodes In

^ 121 -

such a way that their connection with the adult form Is made clear# A trinomial system of nomenclature for the ’cystic cestodes’ would be a slii^le matter, e#g# the polycercal larva of Parleterotaohl^ naradoxa could be known simply as Polycereus .Rayléterofaenla .p.aradoxa» or, if the Latin grammar is to be invoked, Polycercus,parlpterot*enia# narqdojxqq# but It would be even simpler to give the larva the name of the adult as IS the practice In dealing with other classes of the animal kingdom#

APPENDIX III.

The Genus Paricterotaenia Fuhmann

Phylum Platvhelminthes» Glass Cestodas Order GVolophvllideai Family Dlleoldidaes Sub-family Dilepldinae. the uterus sac-like, persistent# more or less lofoed or branched or, rarely, ring-shaped or reticulate; Genus Paricterotaenia. single crown of hooks, genital apertures alternating irregularly, genital ducts between excretory canals, testes numerous, lying behind the female organs; Genotype P. porosa Rudolph! 1810*

Paricterotaenia naradoxs (Rudolph!*

Joyeux and Baer (1939) describe P. oaradoxa (Amoebètaenia lumbrici) as follows (extract)*

’* Length about 1 mm* Greatest breadth ISOp,,

Scolex measures 200*2%! in diameter, the rostellum being half-invaginated in its interior. The suckers are 90-135p, (in

diameter)* The rostellum is 250-340p long, with a maximum diameter of yo-lOOfi# There is a simple crown of 16 hooks of length 87-92|x.

The genital pores alternate* There are 7-9 testes, rarely 10, in the posterior part of the proglottis# The cirrus sac is fairly large, 62-67p long by 25-30p in diameter* It passes the ventral excretory vessel and contains a seminal vesicle #iich is difficult to see# The cirrus Is armed.

The ovary is foilofoed, the vitelline gland large# The seminal

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receptacle, oval in form, measures 50p by 2 % in the third proglottis. The inner shell of the ripe egg measures 27p, in diameter; the outer shell is imperfectly formed. The embryo is 20p in diameter,"

This description is in accord with my observations but it differs from that of Fuhrmann (1936) who, among other things, gives the length of the cestode as 1-12 mm. and the number of testes as 20. As stated by himself, FWirmann was obviously dealing with a

’composite species’ probably including P. naradoxa# P#_ burti and P. stellifera.

According to Fuhrmann, ,P. paradoxe, is "adult in the Woodcock, a<LS^'èâ£2ia L.; the Snipe, GaUlaaaaJM^ (Lath.),

laiAinaqo L, and Lvmnocrvptes oal1inula (L,); the Oystercatcher, Ha,ematgpi^G,o^tz^^^ L.; the Plover, Oiaradil^^

the Lapwing# ^n^Uus ,v^r^U^ L. and the Phalarope# lobatus (L.) - Development unknown."

2Bri.ctergtam^^ Sandman.

Sandeman (1958) describes P*. bui^_ as follows»

"Syn. Paricterotaenia stellifera (Krabbe. 1968) ex parte. Host» Lvmnocrvptes minimus and Numenius arguatus»

The strobila is exceedingly small# it has a length of up to 0.6 mm# and a maximum breadth of 0*17 mm. There are only two or three segments# the last of which is often gravid* The scolex has a diameter of 130-260p„ The rostellum, of length 65p, and breadth

124 -

about bearo a elnglo crovm of 14*16 hooks of length 44*58p# The genital pores ore alternating and open on the loterol margin of the proglottlo, slightly anterior to the oontro# The longitudinal canals were not observed* There are S-8 testes of dimeter 4 % altuatod in the posterior part of the proglottla* The cirrus SCO runs obliquely forwards from the genital pore# it has a length of 54-7<%i by 10-13p* The ovary has two rou%^ed lobes and Is situated centrally in the anterior centre of the proglottis where it is expanded to form a reoeptaculum somlnls of slzo 33;L by ICp* The uterus is sac-liKe and ocouplos the whole ventral part of the proglettls. The eggs have a diameter of 15-17p,*"

p., papai^qx^. is normally associated with other cestodes In the intestine of the Woodcock* Almost without exception# the Woodcock which I have examined have harboured large numbers of Haoloparaxis R»arqfil%.# and sevm?al members of an unidentified species of the

GAnw described bblow# is usually confined

to the middle part of the Intestikie and % havo never found it in the duodenum* The An^pebotsepi^a also occurs in the mid-gut but extends

forwards into the posterior part of the duodenm and backwards Into the third quarter of the gut# In addition, as has Wen mentioned

previously, it 16 not unusual

find 2&.W.E&

ft-pwwkxs,

None of these tapeworma have any obvious effect on the occurrence AltWugh the latter occurs In Its highest concentra­ tions in the anterior part of the duodenum# it is widespread throughout

* 125 -

the anterior two-thirds of the Intestine* It Is found In the Immediate vlclhlty of H* oarafllum and A#ebgtaenla @p* so they, apparently# do not Induce any reaction In the host nor produoe any secretions which prevent the occurrence and development of P* paradoxa In the same host# or vice versa. Such ’acquired Immunity’ has been suggested as an explanation for the fact that certain tapeworms occur In surprisingly small numbers in some hosts and# also# It would

explain the occupation of certain regions of the host’s gut by single species while other species may be found only In other well-defined regions characteristic of these species*

• 126 *•

APPENDIX IV.