| OCR Text |
Show 1895.] ME. F. E. BEDDAED ON NEW EARTHWORMS. 213 which is rather limited in extent; in only one species does it occupy more than segments xiii.-xvii.; in the New-Zealand species the clitellum often extends back to the xixth segment. The American species, too, are never of large size ; a great many of them are very darkly pigmented, a circumstance which is only met with in Acanthodrilus smithii among New-Zealand Acanthodrili. It is interesting that many of these species live equally well in fresh water and on land. Acanthodrilus clcdei, for instance, and Acanthodrilus pictus occurred in Dr. Michaelsen's collection from freshwater gatherings as well as from those in forests. This peculiarity of the genus is not, however, confined to the South- American representatives. The New-Zealand Acanthodrilus paludosus and the Australian Acanthodrilus schmardce also were collected from freshwater sources. I shall now commence the enumeration of the species collected by Dr. Michaelsen. In the description it will be understood that in all species the nephridia are paired, the dorsal vessel single, the spermathecae in viii., ix., and, of course, the ovaries in xiii. (1) Acanthodrilus decipiens, n. sp. To a single specimen of Acanthodrilus from near Estancilla, Province of Valdivia, I give the name of "decipiens" on account of its strong superficial likeness to a Microscolex. I had at first passed it over as an example of that genus, which occurs in the same region. This species is one of the smallest of Acanthodrilus ; the measurements were : length 85 mm., diameter 2-3 m m . The number of segments of tbe worm were 110. The colour (in alcohol) is of a rich brown above, the setae being implanted within white circles. The prostomium is continued over the buccal segment by parallel furrows. The setae are paired, but not so strictly as in Acanthodrilus clcdei, for instance. The implantation of the setae is such as to give to the posterior part of the body a quadrangular aspect. The clitellum occupies segments xiii.-xvii. Dorsal pores are present. There appear to be small median genital papillae upon segments xvii. and xix., with a larger also median papilla upon xx. As there was only a single specimen of the worm, I am not able to give a complete account of the internal structure, which, however, shows no specially interesting peculiarities. The gizzard is very large and stout, relatively to the size of the worm. The spermathecae have each a single good-sized diverticulum. The spermiducal glands extend through two or three segments only; the penial setae, of which I found seven mature and immature in a single bundle, are of a fair length, but are not ornamented. Hab. St. 41, Estancilla, Valdivia. A larger specimen from St. 47 measured 40 m m. |
