. The fur seals and fur-seal islands of the North Pacific ocean. Sealing; Seals (Animals). ASCARIS DECIPIENS. 115 Oar examination of the oesophagus of the Bering Sea form gives the same results which Jagerskiold obtained in studying parasites of the same species taken from Halichoerus grypus. Figs. 16,17 bring out this point very clearly, so that it is scarcely necessary to repeat the description, although it may be remarked that the intestinal caecum may be long or short, in some cases so short as to appear almost absent, while it is usually concave on the surface which rests upon the oesopha
. The fur seals and fur-seal islands of the North Pacific ocean. Sealing; Seals (Animals). ASCARIS DECIPIENS. 115 Oar examination of the oesophagus of the Bering Sea form gives the same results which Jagerskiold obtained in studying parasites of the same species taken from Halichoerus grypus. Figs. 16,17 bring out this point very clearly, so that it is scarcely necessary to repeat the description, although it may be remarked that the intestinal caecum may be long or short, in some cases so short as to appear almost absent, while it is usually concave on the surface which rests upon the oesophagus. • The adult males (fig. 9) vary from 33 to 63""" in length by 1 to ™'° in diameter; the body is slightly more attenuated toward the anterior than toward the posterior extremity; the latter (flg. 18) is curled ventrally; it appears somewhat flattened. Kg. 14. Fig. 13. dorso-ventrally, and upon closer rtudy is seen to possess a rounded keel-like dorsal ridge, with lateral alae which are curled ventrally, giving the ventral surface a concave spoon-like appearance. Numerous caudal papillae (figs. 18, 19) are present. The six pairs of postanal papillae (flg. 19) are divided into two groups; 1, 2, and 3 are nearer the tip of the conical tail and increase in size so that 2 is larger than 1, and 3 larger than 2; occasionally one or another of these papillae are absent; 4, 5, and 6 are nearer the cloaca, and of these 5 is larger than 4 or 6. The praeanal papillae are arranged in a single or doable row eacsh side, and increase in size from the cloaca short distance in front (about praeanal Ifo. 7 or 8), the papillae farther forward being slightly smaller. The spicules are nearly equal in size, ™'" Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Dept. of
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