H. A. Baylis 
373 
3. Ascaris rosmari, new name (= Ascaris tricolor Baird). 
(PI. XV, fig. 3; PI. XVII, fig. 3.) 
Ascaris bicolor Baird (1868), p. 71, Text-figs. A-C; Murie (1868), p. 67; Stiles and 
Hassall (1899), p. 138, Figs. 52-56 (copied from Baird). 
[nec Rudolphi (1793).] 
Of this species, as in the case of A. similis, the only description at 
present available is that of Baird, who confined himself to the examina¬ 
tion of the external features. Stiles and Hassall examined some of the 
cotypes, but were unable, from the material they had at their disposal, 
to do more than add a few details (1899, p. 142). All the specimens 
seen by them were females. 
Baird’s original description is very brief, and it may be well to 
quote it in full: 
“Ascaris bicolor Baird. 
“ Head naked; labia distinct, prominent, rounded, and of moderate 
size. Both anterior and posterior portions destitute of alae or wings. 
Body of worm cylindrical, attenuated anteriorly, of a brownish colour, 
except at the anterior extremity, which is white; the posterior extremity 
is sometimes red. The surface of the body is beautifully and minutely 
but distinctly striated across; as seen under the microscope (with a 
power of two-thirds of an inch), the striae on each side terminate in 
such a manner that the edges of the body appear as if serrated. Caudal 
extremity thicker than anterior, obtuse, and generally convoluted. 
“A great many specimens were found in the stomach [of a walrus]; 
but apparently all were females. 
“The Ascaris simplex of Rudolphi, found in the stomach of the 
porpoise ( Phocaena communis ), very nearly approaches this species in 
general appearance and size, but differs from it in several respects. 
“ The Ascaris bicolor is less attenuated at the anterior extremity than 
the A. simplex , and is destitute of alae or wings equally at the posterior 
and at the anterior extremity. The striations on the surface of the 
body are much finer, and the labia or valves at the mouth are more 
distinct and larger. 
“ Length from 2| to 3 inches; breadth from 2 to 2^ mm. 
“ Hob. Stomach of a young male walrus ( Mus . Brit.).” 
The account given by Dr Murie (1868) of the effects of the worm 
upon its host, is interesting from a pathological point of view, but does 
Parasitology vm 2i 
