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Show 1903.] ENTO-PARASITES OF THE " SKEAT EXPEDITION." 149 ACANTHOCEPHALA. Fam. ECHINORHYNCHID^:. ECHJNORHYNCHVS PATANI, n. sp. (Plate XVI. figs. 9 & 10.) The encapsuled larva? of Echinorhynchida? are by no means uncommon in snakes, and von Linstow * suggests that their corresponding adult forms are to be looked for in the bodies of raptorial birds. In the paper referred to, he enumerates species of these parasites taken from snakes the names of which he gives. Unfortunately many of the names are nominee nuda, and the hosts cannot now be identified, and the same is the case with the new species here described, as the name of the snake was not preserved. The cysts are at most 10 m m . long by 5 m m. broad. The worm is bent twice, and the three limbs may lie in one plane or in two. One of the specimens had escaped from its cyst, and had already inserted its spiny head into some piece of tissue from which it was well nigh impossible to free it. Another had freed its head. and straightened out its body, which, however, was still surrounded by a thin film-like sheath of tissue. The length of these specimens was 25 mm., the breadth of the trunk was 2 mm., of the head 1 m m . The hooks were arranged in 12-14 longitudinal rows, the hooks of one row being at the level of the space between two neighbouring hooks of the row right and left (PI. XVI. fig. 10). In this way the hooks in the horizontal rings also alternated with one another. There were six of such rings, and the second and third row consist of markedly large hooks, twice as large at least as any of the others. Altogether there were six rings visible; there may have been one or more hidden by invagination, but I do not think so. It is most unfortunate that the name of the snake which harboured this parasite is unknown, but the parasite seems to be a hitherto undescribed species. The names of those already known to be encapsuled in snakes are recorded by von Linstow as follows :- (i.) Ech. oligacanthoides Rud., with 4-5 rows of hooks. (ii.) Ech. ductus Rud., with 140 rows of hooks of similar size. (iii.) Ech. obligacanthus Rud., with 13 rows of hooks. (iv.) Ech. megacephalus Westrumb, with very numerous rows of hooks and the proboscis swollen in the middle. (v.) Ech. dipsadis von Lins., with some 12-14 rows of large hooks, followed by 20 rows of smaller hooks. (vi.) Ech. heterorhynchus Par. Proboscis anteriorly slender with 11 rows of hooks, posteriorly enlarged with 16 rows of hooks. Wedl has mentioned other larval forms found in snakes, but they are not in any case specifically identified. * Arch. Naturg. 54 Jahrgang, i. 1888. |