From D. cordatus it is distinguished by—(1) D. cordatus has only fifty immature segments, D. parvus has at least 200, possibly more; (2) mature segments of D. cordatus measure 7 to 8 mm., maximum width of D. parvus is 5 mm.; (3) quadrate segments of D. cordatus measure 5 to 6 mm.; (4) D. cordatus has six to eight uterine loops; (5) D. cordatus measures 75 µ to 80 µ by 50 µ.
Habitat.—Intestine of man (Syrian, in Tasmania).
Genus. Diplogonoporus, Lönnbrg., 1892.
Syn.: Krabbea, R. Blanch., 1894.
The scolex is short and has powerful suctorial grooves; no neck; the proglottids are short and broad; there are two sets of genital organs side by side in each segment, which in all essentials resemble the single one of Dibothriocephalus.
Parasitic in whales and seals, occasionally in man.
Diplogonoporus grandis, R. Blanch., 1894.
Syn.: Bothriocephalus sp., Ijima et Kurimoto, 1894; Krabbea grandis, R. Blanch.
Scolex unknown; chain of proglottids over 10 m. in length, 1·5 mm. broad anteriorly, 25 mm. broad posteriorly. The proglottids are very short (0·45 mm.), but 14 to 16 mm. broad. On either side to the right and left of the worm, along the entire ventral surface, there is a longitudinal groove; these grooves are nearer to each other than to the lateral margin; in them lie the genital pores, and they are in the same sequence as in Dibothriocephalus; corresponding to the scanty length (0·45 mm.) of the proglottids, the ovary is only developed transversely; the uterus only makes a few loops. Eggs (fig. [195]) thick shelled, brown, 63 µ by 48 µ to 50 µ. This parasite has hitherto been observed twice in Japanese. Similar species are known in Cetacea and seals.