Type host: Duttaphrynus melanostictus (Schneider, 1799), Black-spined toad.

Other hosts: None reported to date.

Type locality: ASIA: India, Calcutta.

Geographic distribution: ASIA: India.

Description of oocyst: Oocyst shape: shperoidal; number of walls: 1 (line drawing of Ray 1935a) or double-layered with outer one thicker (Mandal, 1976); wall thickness: unknown; wall characteristics: colorless and very delicate; L x W: 9.8 (8-11 x 8-11); L/W ratio: 1.0; M: absent; OR: absent; PG: absent. Distinctive features of oocyst: colorless, thin, fragile wall.

Description of sporocysts and sporozoite: Sporocyst shape: fusiform or spindle-shaped (pointed at both ends); L x W: 4.5-6.5 x 3; L/W ratio: ~2.0 (Mandal, 1976); SB: absent; SSB: absent; PSB: absent; SR: present; SR characteristics: irregular mass of small granules in center of sporocyst (line drawing); SZ: sausage-like (line drawing of Ray, 1935a) with 1 end more pointed than the other and a centrally located N. Distinctive features of sporocysts: small, spindle-shaped body pointed at both ends and 4 of them do fill the interior of the oocysts (line drawing).

Prevalence: 2 0f 200 (1%)

Sporulation: Endogenous, strictly within host intestinal epithelial cells.

Prepatent and patent periods: Unknown.

Site of infection: Epithelial cells of the small intestine.

Endogenous development: There are two kinds of meronts: macromeronts, 12 x 6, which release 20–30 merozoites, which develop into macrogamonts, and micromeronts, producing 6–8 merozoites, 3 x 1.3, which give rise to microgamonts with numerous uniflagellate microgametes. Early micromeronts were readily distinguished from macromeronts by the absence of darkly staining granules in their cytoplasm; early forms were 6 x 2 and mature forms were 12 x 5.5 with 6–8 merozoites, arranged parallel to the long axis of the meront. Ray (1935a) said that it was these merozoites that produced the male forms of the parasite. The mature microgamonts measured ~13 x 9 and showed numerous N at the periphery. Fully formed microgametes were 2.8–3 x ~1, with a single flagellum at 1 end about the same length as its body. Early macromeronts have “from a very early stage dark-staining granules scattered through the cytoplasm” (Ray 1935a). Fully mature macromeronts within the host cell were spheroidal, 9–10 wide when filled with up to 30 merozoites, each with darkly-stain ing granules in their cytoplasm. Fully developed macrogamonts were 11 x 5.6 with a spherical N, ~3. Both micro- and macromeronts were seen to have a structure at one end that Ray (1935a) called a hyaline laminae. Fertilization, oocyst formation, and sporulation all occurred intracellularly.

Materials deposited: None.

Remarks: Ray (1935a) looked at fresh smears of frog rectal and intestinal contents in saline and saw what he said were, “active gregarinulae...in large numbers,” which he later said were liberated merozoites of two sizes. Very little information about the sporulated oocyst is included in the original description, although description of other life stages is given. Mandal (1976) gives a sporulation time of 60–72 h, conflicting with the original description of endogenous sporulation (Ray 1935a, b).