Bucephalus longicornutus (Manter, 1954)
(Text-fig. 9, A-J.)

1954. Alcicornis longicornutus Manter, p. 482.

Host: Kathetostoma giganteum Haast, monkfish; family Uranoscopidae.

Location : Pyloric caeca and intestine.

Locality: Cook Strait (type locality); Foveaux Strait.

Description (24 gravid specimens were studied and 12 were measured; 3 specimens were sectioned; measurements in mm) : Body elongate, truncate anteriorly tapering posteriorly. Total length varies between 0.73 and 2.86 (average approximately 1.6) and greatest width varies between 0.3 and 0.66 at approximately ovary level. Cuticle spinose, apart from anterior sucker concavity, tentacles and ventral to prominent radial muscles of anterior sucker. Spines more sparse over posterior third of body. Anterior sucker 0.2 to 0.3 long by 0.23 to 0.26 wide at its anterior margin. Seven tentacles surmount anterior sucker; three dorsal, two lateral, two ventral. Each approximately 0.09 to 0.11 long by 0.02 wide, having one thorn-like process, approximately 0.03 long, near base (Text-fig. 9, B). Tentacles retracted in most specimens but a complete series from almost fully extended to fully retracted obtained. Each tentacle, with muscular core which extends into the thorn-like process, bears a slight depression at its truncate or occasionally rounded distal end. Sucker musculature essentially scoop-shaped and three, occasionally five, tentacular ducts, continuous with free ends of tentacles, prominent in dorsal musculature. Prominent gaps between groups of oblique muscles along anterior margin of sucker coincide with positions of emergence of free ends of tentacles. Ducts for ventral pair of tentacles not observed. When ventral tentacles are completely retracted their points of emergence from musculature are marked by small, but conspicuous, ventral depressions. Prominent band of radial muscles, 0.05 to 0.06 wide, U-shaped or semicircular, around posterior margin of sucker concavity. Cuticle overhangs these muscles and demarcates posterior limit of the sucker concavity. Cuticle does not completely close off open end of musculature and spines on this part of cuticle are not always seen. Musculature U-shaped in transverse section and seven gaps between muscle fibres seen corresponding to seven tentacular ducts.

Mouth generally anterior to mid-body level, varying between 0.33 and 0.56 from anterior extremity. Pharynx, ovoid to spherical, 0.07 to 0.12 long by 0.07 to 0.12 wide. Eggs obscure oesophagus in material examined. Intestine ovoid, 0.2 to 0.3 long by 0.13 to 0.19 wide, dorsal in position and directed posteriorly, often obscured by eggs.

Testes, ovoid to spherical, 0.13 to 0.2 long by 0.1 to 0.2 wide, on right side of the body, generally between intestinal and mid cirrus sac levels, diagonal in most specimens but occasionally tandem. Anterior testis usually touches posterior margin of ovary but in one specimen it overlaps ovary ventrally by approximately page 34

Text-fig. 9.—Bucephalus longicornutus. Morphology and anatomy of adult specimens from Kathetostoma giganteum Haast: Fig. A, ventral view of a specimen with the tentacles partly retracted; Fig. B, left lateral view of a specimen with the tentacles extended; Fig. G, ventral view of the anterior sucker with the tentacles almost completely retracted; Fig. D, ventral view of the anterior sucker with the tentacles completely retracted; Fig. E, ventral view of an immature specimen; Fig. F, ventral view of the Mehlis's gland complex; Fig. G, detail of a tentacle; Fig. H, normal operculate egg; Figs. I, J, abnormal eggs. For abbreviations see p. 9.

page 35 0.08 and in two specimens it is separated from ovary by approximately 0.02. Posterior testis usually touches anterior testis but in two specimens, it slightly overlaps anterior testis dorsally and in two specimens it is separated from anterior testis by a narrow gap. Vasa deferentia not observed. Cirrus sac, 0.4 to 0.64 long by 0.09 to 0.15 wide, extends to about mid-body level. In one specimen, proximal third of its length is bent at right angles to distal two-thirds. In remaining specimens it varies from straight, to crescent-shaped to sigma-shaped (Text-figs. 9, A and B). Cirrus sac consists of ovoid seminal vesicle, 0.09 to 0.13 long by 0.08 to 0.1 wide, and long pars prostatica. Genital atrium, 0.19 to 0.3 long, contains a smooth or corrugated genital lobe, 0.1 to 0.17 long. Gland cells surround genital atrium. Genital pore varies between 0.08 and 0.11 from posterior extremity.

Ovary generally spherical (but in five specimens ovoid), varies between 0.1 and 0.13 in diameter or 0.1 to 0.11 long and 0.12 wide, on right side of body at approximately intestinal level. Oviduct emerges from right side of ovary, opens into ootype, 0.01 to 0.02 posterior to ovary and gives off Laurer's canal approximately one-third from its proximal end. Laurer's canal runs obliquely towards dorsal midline and opens to exterior at approximately anterior testis level. Uterus emerges from posterior margin of ootype and was traced posteriorly to intertesticular level. Remaining coils indistinct.

Vitellaria arranged in two lateral groups between sucker and pharynx. Individual follicles clumped or spread and this can be related to number of eggs in uterus. Most often, 16 follicles on each side but this number can vary between 14 and 18. Each follicle more or less spherical, between 0.04 and 0.06 in diameter. A difference of 0.005 generally exists between extremes in sizes of follicles in a given specimen. Left vitelline duct runs obliquely to posterior testis level then loops and runs anteriorly on right side of body to enter vitelline reservoir immediately median to ootype. Right vitelline duct runs slightly obliquely and enters vitelline reservoir. Short duct connects vitelline reservoir with ootype (Text-fig. 9, F).

Eggs occupy most of body in most specimens. Their anterior extent is variable. In two specimens they extend just beyond pharynx level but in most they reach to within 0.1 to 0.18 of posterior limit of sucker. Eggs extend posteriorly to level of genital pore. They are ovoid, distinctly operculate, 0.021 to 0.035 long by 0.015 to 0.022 wide (Text-fig. 9, H). Two specimens contained a few abnormal eggs (Text-fig. 9, I, J).

Excretory pore terminal and saccular excretory bladder extends just anterior to pharynx. Flame cell formula not determined.