-i± THOMPSON YATES LABORATORIES REPORT 
... 
The ovum, containing a coiled-up embryo, measures 2~j"j n by 19*5 m- The 
embryo is 112^ long by 4-2 m wide. 
The male is much shorter than the female, and very active when freshly 
introduced into normal salt solution. It is very slender, and has a well marked 
incurved tail. It measures 1 1*6 to 14*8 mm. long, and its breadth averages C136 mm. 
Cobb's formula : — - 1 2 53> — 50, 98 8 
— , 1.04, 1 -o 4 , 1-38, 0-69 
The cuticle is striated and ridged as in the female. The head end (plate VII, fig. 4) 
is also similar to that of the female. The mouth is terminal and simple : there are 
no appendages. 
The length of the oesophagus is 0-03 mm., there is no bulb. The anal orifice 
is at o - 1 49 mm. from the tip of the tail. The reproductive system consists of a 
single tube commencing thin, gradually increasing in width and occupying the greater 
part of the body cavity ; it seems to end in connection with the bases of the spicules. 
The tip of the tail (plate VII, fig. 5) has four papillae, two of which are terminal so 
that the end appears bifid : the other two are placed dorso-ventrally to these and are 
much smaller. In front of these on the ventral surface are four papillae arranged in 
two pairs ; while still further forward are two other post-anal papillae on each side ; 
no pre-anal papillae could be made out. There are two unequal spicules, in many 
of the specimens extruded. (Plate VII, fig. 5, and plate VIII, fig. 1). The orifice 
(16-3// across) through which they protrude resembles a wide crater with sharply 
defined edges at the summit of a low cone. The dorsal spicule seems to widen at its 
base and embrace the ventral ; this spicule is pointed. 
The embryos are found in the peripheral and central blood. The length 
varies very much in the fresh condition from 91 to 107*5 V- '■ tne embryo can be 
seen stretching itself considerably. Breadth 3*26 jx. There is no sheath (plate XIII, 
fig. 5). The head end is blunt and there is some differentiation into a small papillae 
bearing a short stumpy spine. The tail end tapers a little and ends bluntly. The 
contents of the body of the worm are somewhat closely granular. In the fresh 
condition this embryo is characterised by the possession of a very distinct oval very 
highly refractile globule behind the middle point of the worm, almost at the junction 
of the middle and posterior thirds. 
In stained specimens (plate VIII, fig. 2) the embryos only measure 87-3 ^ on 
an average. The anterior bay in the column of cells at the head end is well marked. 
The cells in these specimens appear to be loosely arranged. Four spots can 
sometimes be seen, but three of them are extremely variable. Sometimes one only, 
sometimes two, three, or four are present. One is constant — the third, and is a 
distinguishing feature of this embryo. 
1. A small slit at a distance of 25-4 per cent, of the length of the worm. 
2. A V which may extend across the breadth of the worm, distance 34*4. 
