42 
THE VOYAGE OF H.M.S. CHALLENGES. 
testicular portion bears numerous and variously sized ovarian follicles. The hermaphro- 
dite duct takes its course along the furrow on the under surface of the gland, and is 
formed of numerous ductules (fig. 17,. a), which unite together ; it passes over to the 
posterior portion of the mucous gland and swells out into an ampulla. — The anterior genital 
mass is longish and roundecl-subquadrangular in shape ; it is more convex upon the upper 
side than upon the lower; its length is 9 mm., breadth 7 mm., and 5'5 m m. in height. 
On the upper side are the windings of the yellowish, strong vas deferens, which ends 
in front in the large penis; the latter forms the anterior end, and is generally more than 
one-half of the genital mass. The backward continuation of the vas deferens passes 
round the left margin of the genital mass, and runs along its under surface as far as the 
ampulla of the hermaphrodite duct, which latter forms the hinder end of the genital 
mass. The ampulla, which is situated beneath the hinder end of the genital mass, is 
yellowish in colour, small, and rather thin. The vas deferens is long and strong, its 
length is 4*5 cm., and the diameter everywhere 1 *5—1 mm.; the longer hinder part of it 
(fig. 20, c) probably acts as a prostate gland, it is yellowish in colour, but somewhat less 
stout than the anterior muscular portion (fig. 20, b), which is about 1*6 mm. long; these 
two divisions are separated by a constriction (fig. 20, a). The penis is short and sac- 
like, slightly arched, 8 mm. in length with a diameter of 4 mm.; the wall is rather thick, 
the structure of the whole organ resembles that of other species of Bornella. The short 
inferior portion is unevenly wrinkled on the inside ; the remainder is smoother and 
lies between two similar stout festoons. These structures are usually 1-1*5 mm. in 
thickness and the same height ; they unite with each other below (fig. 19) and above 
(fig. 18) the circular orifice (fig. 18, a) of the vas deferens ; they have the margins as well 
as the surface somewhat wrinkled. On the margin are developed a number of black 
spines (altogether about 220) arranged in a single row. These spines (figs. 21, 22) are 
found in furrows at the rounded summit of cones, about twice as high as the spines 
themselves ; the tissue of these cones is prolonged for a short distance up the axis of 
the spines, which are therefore very firmly attached, and do not easily break off. The 
straight, slightly S-shaped spines are of the average height of *28 mm.; their contour 
is rounded ; they are broader below, and end in a point above. The spermatheca 
is pear-shaped, about 2 mm. long, and lying on the right side of the mucous gland, it 
was distended with semen ; its duct, hardly as long as the organ itself, opens into the 
vestibulum genitale close to the opening of the mucous gland. This latter organ is 
yellowish, but chalky white on the under surface and on the left side ; at the hinder 
end it has a large brown twist, which is blackish-blue above ; the efferent duct is short, 
and has the usual fold. 
The species I have just described is strikingly different from the three other previously 
examined species of Bornella (. Bornella calcarata from the Antilles Sea, Bornella digitata 
