H. Kobayashi 
395 
(13) Cricocephalus koidzumii n. sp. (PI. XXIV, fig. 9). 
Diagnosis. Resembles Cr. albus, but differs from it by (1) its smaller 
size, 3*5-3*8 mm. x 0*8-1 mm., (2) its very sinuate testes, (3) its having no 
trace of a pharyngeal bulb. Habitat: in the intestine of Chelone midas. 
Description. This species was found in the stomach of Chelone midas , 
captured at Singapore. The specimens were collected by M. Miyajima and 
others and were fixed by heat. 
The size is 3*5-3*8 mm. x 0*8-1 *0 mm. Body somewhat flattened dorso- 
ventrally; lateral margins ventrally curved except in the cone-shaped part. 
The posterior end truncated; the broadest part is near the posterior end and 
the body either slightly narrows anteriorly, or both lateral margins run almost 
parallel; at the “shoulder” it abruptly narrows and forms a cone-shaped 
anterior end; protuberant postero-laterally. 
The oral sucker lies near the anterior end of the body, its diameter being 
0*3 mm. The cuticle of the body surface is smooth. The oesophagus is 0*5 mm. 
in length. The intestinal caeca reach almost to the posterior end of the 
body. Each has numerous (20-30) diverticula, which undergo further sub¬ 
division. 
Excretory pore opening at the posterior end of the body. The unpaired 
part of the vesicle runs forward, beyond the level of the posterior margin of 
the testes, and then divides into two. 
Both testes lie symmetrically in the posterior part, their distance from the 
posterior end being 0*4 mm. They lie exterior to the posterior trunk of the 
intestine. They have a somewhat lobate or sinuate form, 4-5 lobes being 
present. The width of each testis is about 0*2 mm. The intestinal caeca bend 
inwards at the place of attachment of the testes. The vesicula seminalis lies 
in the anterior part of the posterior half of the body; it is a broad canal with 
numerous irregular lateral bends. The cirrus-pouch is spindle-shaped and 
continues ant.eriorly into the ductus ejaculatorius. , 
The ovary lies slightly anterior to the level of the testes, somewhat to the 
right of the median line. It has somewhat irregular lobes, and its diameter 
is 0*15 mm. Postero-medially to the ovary are the shell-glands. The vitellaria 
are small, lying exteriorly to the intestinal caeca. They extend shortly anterior 
to the level of the ovary. Each gland consists of about 15 groups. The uterus 
is surrounded by the intestinal caeca, the ovary, and the posterior end of the 
ductus ejaculatorius. It has many transverse loops which lie in close contact 
with one another. The vagina is very well developed, running along to the left 
of the ductus ejaculatorius. The distal part of the vagina has long spines in 
its cuticular wall. 
The genital opening lies left of the median line 0*7 mm. from the anterior 
end of the body. A short genital sinus is present. 
The egg bears long, whip-like appendages at both poles. The size of the 
normal egg is 0*02 mm. x 0*01 mm., while the length of each appendage is 
Parasitology xii 26 
