Hyphae much branched, up to 6.5 µ diam., numerous vesicles present, up to 30 µ diam. Sporangiophores arising from substrate mycelium, single or clustered, simple, erect, non-septate, 340-930 (av. 560) µ long, obclavate, tapering from basal width of 28-65 (av. 45) µ to apical width of 21-46 (av. 36) µ. Apophysis 36-70 (av. 56) µ diam. Sporangia solitary, spherical, 63-158 (av. 100) µ diam. Columella inconspicuous to absent, up to 17 µ high. Spores reniform to sinuate allantoid, 13-23 (av. 18) µ long, 4-8 (av. 5.8) µ diam. Apically appendiculate. Appendages simple, vermiform, 20-35 µ long, 1.5 µ diam. at tip. Sexual spores unknown. Habitat: Fresh water, on Neocurupira campbelli pupae, Bealy River, Arthur Pass, New Zealand. Type: U. C. Berkeley, 1317750.

Hyphae multum ramosae, usque 6.5 µ diam.; vesiculae multae usque 30 µ diam. absunt. Sporangiophorae mycelio in substrato enascentes, unicae vel fasciculatae, simplices erectae, non septatae, 340-930 (av. 560) µ longae, obclavatae, decrescentes a 28-65 (av. 45) µ diam. in basi ad 21-46 (av. 36) µ diam. in apice. Apophysis 36-70 (av. 56) µ diam. si praesens. Sporangia solitaria, sphaerica, 63-158 (av. 100) µ diam. Columella inconspicua usque absentia, usque 17 µ alta. Sporae reniformes usque sinuate allantoidea, 13-23 (av. 18) µ longae, 4-8 (av. 5.8) µ diam., apicaliter appendiculatae. Appendices simplices, vermiformes, 20-35 µ longae, 1.5 diam. apice. Sporae sexuales incognitae. Aquam dulcem vel pupas Neocurupira campbelli habitat, New Zealand. Typus : U. C. Berkeley, 1317750.

The mycelium of A. elegans fills the abdominal cavity of the insect pupa, and the sporangiophores (Fig. 1) are formed singly or more typically in tufts, protruding between the plates of the exoskeleton. Whether the fungus is an active parasite or a secondary saprophyte remains to be determined.
The hyphae are much branched and numerous vesicles, both intercalary and terminal, are present (Fig. 2). Hyphal anastomoses are also to be found. The sporangiophores originate as hyphal vesicles which enlarge and elongate to form tapering unbranched stalks (Fig. l, 3). The spherical sporangium at the apex of the sporangiophore is subtended by an apophysis which, though often inconspicuous, is a constant feature of the species (Fig. 4). The sporangia and sporangiophores vary greatly in size, and no relationship in size between the two has been found.
The morphology of the sporangiophores is the most distinctive feature of A. elegans. The initial cleavage pattern gives rise to numerous vermiform spores up to 95 µ in length (Fig. 6). As a spore matures the cytoplasm is retracted from the ends to the central region and walls are formed delimiting this area. At maturity the terminal portions are devoid of cytoplasm with the exception of a thread-like central strand extending from the tip to the central body of the spore (Fig. 7, 8). The empty terminal portions are flexuous and act as spore appendages; no evidence of an adhesive nature has been found.
The sporangiospores are released either by a dissolution or a rupture of the wall at the apex of the sporangium (Fig. 5). In empty sporangia the basal wall separating the sporangium from the apophysis protrudes upward to form a very reduced columella. This protrusion is not seen in immature sporangia.
A. elegans is the only known member of the Mucorales in which sporangiophore formation and spore discharge occur normally under water. The spore form is also unique in this order and presumably is an adaptation to the aquatic habitat. A. elegans has its greatest taxonomic affinity with the genus Mortierella Coeman. The general morphology of the sporangiophore, unbranched, robust, and tapering upward from a swollen base, is similar to that of species of Mortierella in the section Polycephala (Linnemann, 1941). The presence of hyphal vesicles and anastomoses, and the rudimentary columella are all features that the two genera have in common. A. elegans is therefore placed in the Mortierellaceae as summarized by Hesseltine (1955) and is distinguished from the genus Mortierella by its aquatic habit and the appendiculate nature of the sporangiospores.