The animal family Almidae includes about six genera of
segmented worms.
A notable peculiarity of some species in this family is a tendency to extensions of the body wall in the vicinity of or including the male pores. These extensions may be mere protuberances, as in some species of ''Drilocrius''; or involve a greater extent of the body wall, as in genus ''Glyphidrilocrius''. They take the form of wing or keel-like structures called alae in ''Glyphidrilus'' species and paddle-shaped claspers in ''
Drilocrius alfari''.
All species of genus ''Alma'' have claspers. The male pores are near the tips of these claspers, and they are furnished with genital
chaeta
A chaeta or cheta (from Greek χαίτη “crest, mane, flowing hair"; plural: chaetae) is a chitinous bristle or seta found in annelid worms, (although the term is also frequently used to describe similar structures in other invertebrates such ...
e and sucker-like structures.
Most members of this family have one pair of male pores on segment 15 through 30. Female pores are located on segment 14. ''
Glyphidrilus kukenthali'' is one of only three ‘earthworm’ species known to have two pairs of female pores, in 13 and 14.
A possibly related family,
Criodrilidae
The family Criodrilidae is represented by genus ''Criodrilus'' comprising limicolous (mud-dwelling) and/or aquatic earthworms endemic to the Palaearctic currently known only from Europe and Japan, respectively. Only three or four species are des ...
, contains genera ''Criodrilus'' and ''Biwadrilus'' with male pores in 15 and 13, respectively.
Spermatheca
The spermatheca (pronounced plural: spermathecae ), also called receptaculum seminis (plural: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain othe ...
e are absent (a rare condition in
oligochaetes
Oligochaeta () is a subclass of animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadrile earthw ...
) and one to several
spermatophore
A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores ...
s containing the sperm are transferred between partners and attached near the genital field.
References
Review of Criodrilidae (Annelida: Oligochaeta) including Biwadrilus from Japan
{{Taxonbar, from=Q4733805
Clitellata