a ee ee 
of the Fishery Board for Scotland. 243 
in it an account of the male as well as of the female. In my previous 
record of the species I stated that one of the peculiarities of Botryllophilus 
was ‘“‘the almost constant existence of a single ovigerous sac of a strictly 
spherical form sheltered between the fifth feet.” I now find that this sac 
in the specimens observed, both in the Clyde and the Moray Firths, is 
really composed of two sacs, partly adherent to each other and so closely 
joined as to appear as if they formed but a single globular mass. 
Description of the female.—Length of the specimen figured, 1:16 mm. 
(about ~; of an inch). The cephalothorax, which terminates anteriorly in 
a short ‘bluntly rounded rostrum, is somewhat narrow in front, but 
becomes gradually dilated towards the posterior end and especially on the 
dorsal aspect. Scarcely any trace of segmentation can be made out in 
the cephalothoracic region, but this is probably due to the fact that the 
Botryllus in which the specimen was obtained had been for several years 
(since 1896) preserved in alcohol. The abdomen is narrow and elongated, 
but is rather shorter than the cephalothorax (fig. 15). 
The antennules are very short and composed of four joints, the first is 
considerably dilated, the second is moderately stout but much smaller 
than the first; the third and fourth are small; the antennules are 
furnished with a number of long and moderately stout sete, which appear 
to be devoid of feathering (fig. 17). 
The antennz, which are two-jointed, are comparatively long and slender 
and of nearly equal thickness throughout, they are each composed of two 
(or (#) three) joints; the end joint is provided with three stout spines on its 
inner margin, and a few spines and sete at the apex, the other joints 
appear to be unarmed (fig. 18). The antennz are not provided with 
secondary branches. ~ 
The mandibles and maxillz appear to be obsolete or very rudimentary. 
The first maxillipedes are small and feeble, they are each composed of 
three joints, the second and third joints are sub-equal and rather smaller 
than the first; the first joint is unarmed, the second bears two or three 
spine-like setze on its inner aspect, and the third is provided with a few 
terminal setz of unequal lengths, the outermost being considerably longer 
than any of the others (fig. 19). 
The second maxillipedes are short but somewhat robust, the basal joint 
is moderately distended, and larger than the second one, the third joint 
is very small, the end-joint is narrow and fully twice the length of the 
third and bears a short but strong terminal claw (fig. 20). 
The thoracic feet.—All the thoracic feet, with the exception of the fifth 
pair, are short and robust and composed of two branches. In the first 
and second pairs, the inner branches are very short and two-jointed ; 
about eight plumose sete of moderate length spring from the rounded 
apex of the second joint, and one from the inner margin of the first joint. 
The outer branches, which appear to be uniarticulate, are rather longer 
than the inner ones and are armed with a few small marginal and apical 
spines, as shown in the drawing (fig. 21). In the third and fourth pairs 
the outer as well as the inner branches are two-jointed ; the inner branches, 
which are somewhat alike in both pairs, are rather longer than those of 
the first pair, but their armature is somewhat similar, except that the end- 
joints bear six instead of eight plumose sete; the outer branches of the 
third pair are somewhat similar to those of the first except that there is 
an articulation between the two proximal marginal spines, dividing the 
branches into two joints (fig. 22); the outer branches of the fourth pair 
are less robust than the inner branches, but are nearly equal to them in 
length ; a single small seta springs from near the end of the outer margin 
of the first joint, while the second is furnished with four apical and sub- 
