| OCR Text |
Show 1892.] SPECIES OF EARTHWORMS. 675 The dorsal pores commence between xi./xii. The gizzard measures 8 m m . in length, and appears at first sight to occupy about four or five segments; it really corresponds to segment v., which is increased in size at the expense of neighbouring segments for its reception. The calciferous glands are in xv. and xvi.; they have the appearance of being merely dilatations upon the course of the oesophagus, which is the case with the other species of this genus. The intestine begins in xviii., but the typhlosole (which is very prominent) does not begin before segment xx.; it ends at about 60 segments before the end of the body. The first septum is in front of the gizzard. After the gizzard are six stout septa, and, following these, are two which are rather more developed than the rest, but not as strong as those which precede them. The nephridia are diffuse, and there is a particularly dense mass of tubes in the anterior segments, which seem to represent the mucous gland of Octochcetus multiporus1. The dorsal vessel is double, and there are three pairs of hearts in x.-xii. All the gonads are attached to the front wall of their segments. The spermatothecae (in viii., ix.) have a minute clump of diverticula, presenting the appearance of a solid body, about the size of a pin's head. There are no penial setae. Hab. New Zealand. This species is evidently perfectly distinct from the last; it is, however, clearly referable to the same genus, if this genus be admitted. The diffuse nephridia, double dorsal vessel, separate setae, absence of penial setae, and anterior position of gizzard cause it to resemble the three other species which I refer to the genus Octochcetus. It differs from O. multiporus and from 0. thomasi in the following points :- (1) The prominence of the atrial pores as seen from the outside. (2) The position of the gizzard in segment v., and its limitation to this segment. (3) The presence of two pairs of calciferous glands in xv., xvi.; in this the present species resembles 0. antarcticus. (4) The existence of only three pairs of hearts instead of four. (5) Six thickened septa instead of seven. (6) The attachment of the gonads to the front wall of their segments; in this character 0. huttoni resembles 0. antarcticus. The next species which I describe is referable to the genus Acanthodrilus (s. s.). 3. Acanthodrilus smithi, n. sp. I have been able to examine, though the kindness of Mr. W . W. Smith, some seven examples of this new species of Acanthodrilus ; the general appearance of the worm is very different from that of 1 I did not ascertain whether these opened into the buccal cavity as in 0. multiporus. |
