MACALISTER, ON ASCARIS DACTYLURIS. 81 
conjecture in such a minute species. These lines appear to 
be made up of longitudinal striz, with dark granules in their 
intervals. Anterior and posterior lines are also visible, but 
less distinct in general than the lateral. The tail is very 
variable in shape; in the female it sometimes is short and 
rapidly acuminated; in other specimens it is long, attenuated, 
and occasionally even uncinated at its extremity ; near the 
tip small papillz or elevations are obvious, and in some indi- 
viduals these give an obscure appearance of serration to its 
-margin. The tail of the male is much shorter, blunter, and 
more rapidly narrowed to its rounded end, which is more be- 
velled in its ventral than on its dorsal aspect, to accommodate 
the masculine organs of reproduction. 
The head presents three tubercles, which are nearly equal 
in size, but they are not so distinct as they appear to be in 
other allied species; they exhibit several small irregular 
granulations on their inner or oral aspect ; on using gentle 
compression I was able in several individuals to see a fine, 
slightly curved tube projecting between the three tubercles ; 
this, I think, is similar to the tube referred to by Bremser in 
other species of Ascaris, which he takes to be the true mouth, 
but which appearance Wedl considers to be due to the protru- 
sion of the everted lining of the cleft proboscis. Through it I 
was enabled to evacuate, by gentle pressure, currents of 
granules from the cesophagus. 
In a few of my specimens two lateral ale exist, one on 
either side of the head ; but this appearance seemed rather un- 
common, as I could only find it in about eight per cent. of 
the examined specimens ; when present these wings commence 
immediately outside the tubercles by a raised or prominent 
circular collar, behind which the flat, slightly wrinkled ale 
start and extend backwards and outwards for a short distance, 
when they rather suddenly contract until their margins be- 
come continuous with the wrinkled integument. Though this 
appears the usual disposition of the wings, it is sometimes 
departed from ; as in one individual I saw the wings extending 
down the anterior part of the body for a considerable distance, 
and gradually diminishing until they were lost about half a 
line behind the head ; in one case, also, the naked subglobose 
head was united to the trunk by a narrow neck, which was 
bordered by aslight ala. These variations show, I think, how | 
little these appendages, per se, are to be valued as marks for 
the distinction of species. I could not associate their presence 
with any conditions of age or sex, for though I only saw them 
in females, they were by no means frequent in that sex, and 
seemed completely irrespective of youth or maturity. 
