56 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



0.032 mm. in width. Esophagus slender, bifurcating in region of 

 genital pore. Intestinal limbs extending to half length of haptor, 

 with lateral branches not uniting posteriorly. Genital pore 0.180 to 

 0.271 mm. from anterior end. Genital atrium with numerous straight 

 chitinous rods, 0.016 to 0.200 mm. in length, arranged in a circle. 

 Testes small, numerous (several hundred), smooth, elliptical, closely 

 packed in posterior third of body between ovary and haptor. Ovary 

 in middle of body in mid-line, shape of inverted U, long and slender 

 with arms of approximately the same length, left arm slightly longer. 

 Oviduct arises from right arm. Vitellaria fine, acinous, from anterior 

 fifth to middle of testicular region. Vitelline ducts unite at level of 

 posterior third of ovary. Uterus relatively straight and broad In 

 mid-line. No eggs present. 



Comparisons. G. elagatis has ninety to 100 posterior suckers 

 compared with 120 in G. acanthurum and thirty-seven in G. caran- 

 gxs, one group of genital spines compared with two groups. G. 

 acanthocybii has one group of genital spines but they diifer in num- 

 ber, size, and arrangement; fewer testes (fifty-two to eighty-four 

 testes compared with several hundred in G. elegatis and sixty in G. 

 carangis), and the vitellaria extend only to haptor rather than to 

 middle of haptor region. 



G. elagatis is named after the genus name of the host, Elagatis. 



Genus: Thoracocotyle MacCallum, 1913 



MacCallum (1913) described Thoracocotyle from the Spanish 

 mackerel (Scomberomorus maculatus). It is unique among the 

 Monogenea in that most of the body functions as a haptor. Most 

 of the body proper lies flat on the substratum or attached to the 

 host by suckers along each side while the rest and least conspicuous 

 part of the animal arises dorsally and at right angles to the haptor 

 region. The anterior part of the animal is practically free from organs 

 with the exception of the almost straight uterus and the relatively 

 broad tortuous vas deferens which lies dorsal to the uterus. Ap- 

 parently due to the fact that the anterior part of the animal is free 

 from organs, the vas deferens swings broadly from side to side and 

 occupies about one half the width of this part of the animal. 



Price (1936) places this genus in the Diclidophoridae instead of 

 the Microcotylidae and created a new subfamily, Thoracocotylinae. 



