A Review of the North American Freshwater Snail Genus Pyrgulopsis

NUMBER 554
FIGURE 2.—Morphology of Pyrgulopsis: ajb, whole mount of penis (dorsal [a], ventral [b] aspects), P.
californiensis, SBMNH uncat. (bar = 0.5 mm); c, close-up of a, showing gland cells (bar = 0.25 mm); d, scanning
electron micrograph showing ventral aspect of critical point dried penis, ibid, (bar = 0.38 mm); e, photograph
showing mantle pigmentation pattern, P. lustrica, UF 39160 (bar =1.0 mm). (Dgl = transverse dorsal gland, Dg2
= dorsal gland along left distal edge, Dg3 = dorsal gland along right edge of lobe, Pg = penial gland, Tg = terminal
gland, Vd = vas deferens, Vg = ventral gland.)
right edge, discharging through tip of filament Penis variably
ornamented with one or more glandular units comprised of
rows of narrow gland cells; glandular units superficial or borne
on low swellings or lobules. Ornament may include a penial
gland (rarely multiple)(Pg) covering part or all of dorsal
filament; dorsal glands positioned along right edge and/or
transversing part or all of width near mid-line (often borne on
swelling proximally)(Dgl), along left distal edge (Dg2), and
along right edge of lobe (often borne on swelling or lobule)
(Dg3); terminal gland (Tg) positioned along or near edge of
distal lobe, often fragmented into several units; and ventral
gland(Vg), usually positioned proximal to base of filament and
usually borne on swelling. Additional dorsal and ventral glands
also sometimes present. Penis weakly ciliated. Filament often
darkly pigmented.
Females (Figures 4, 5) oviparous; egg capsules simply
hemispherical, without coating of sand grains, deposited singly
on substrate or shell. Glandular oviduct composed of folded
cells. Albumen gland usually with pallia! section comprising
up to a third of total gland length. Albumen and capsule glands
about equal in size. Capsule gland almost always divided into
two tissue sections, rarely unipartite. Capsule gland with
well-developed ventral channel. Genital aperture a terminal or
subterminal slit often opening to a short anterior gutter. Coiled
oviduct of one or few loops on left side of albumen gland.
Oviduct and bursal duct usually join slightly behind pallial
wall, but sometimes well behind or slightly in front of wall.
Sperm pouches pressed against left side of albumen gland;
bursa copulatrix usually considerably larger than seminal
receptacle. Bursa copulatrix sac-like to broadly ovate, sometimes
with blunt anterior end ("pyriform"), usually moderate in
length relative to albumen gland, positioned on posterior
albumen gland (often extending behind gland). Bursal duct
short-elongate, narrow to near width of bursa copulatrix,