Eumecynostomum evelinae Marcus 1948

Eumecynostomum evelinae (Marcus, 1948)

(Fig. 23)

Mecynostomum evelinae: Marcus 1948 (p 113); Marcus 1949 (p 13); Marcus 1957 (p 173); Ax 1961 (p 26); Ax 1963 (p 65).

Pseudmecynostomum evelinae: Dörjes 1968 (p 84); Ehlers and Dörjes 1979 (p 67). Eumecynostomum evelinae: Faubel and Regier 1983 (p 11).

Material. Living specimens in squeeze preparation; whole mounts for fluorescence imaging of musculature.

Locality. Itaçucê Island, São Sebastião Channel, São Paulo, Brazil, from coarse shelly sand with silt taken from 5 m water depth (23°49’S, 45°20’W).

Description. Living specimens ~ 600 m long and 200 m wide (Fig. 23 A). Body sometimes with red coloration in digestive syncytium and yellow coloration in region surrounding statocyst. Without obvious rhabdoid glands. Large chordoid vacuoles sometimes present at posterior end of body. Mouth opening on ventral surface, middle of body. Mouth surrounded by strong sphincter muscles.

Ovaries and testes paired. Separate male and female gonopores; female anterior to male (Fig. 23 B). Female gonopore opens to bursa via glandular-walled vagina. Bursa with muscular wall. Male gonopore leads to glandular penis (Fig. 23 B). Penis surrounded by a few weak muscle fibers.

Remarks. Eumecynostomum evelinae is the only mecynostomid known to occur in Brazil. Marcus (1948) collected specimens from algae in Santos Bay, Brazil.