| OCR Text |
Show 1895.] MB. F. E. BEDDABD ON NEW EAETHWOEMS. 231 situated on a conspicuous papilla; the end of the spermiducal gland appeared to be protruded, thus forming a second " papilla " of smaller size upon the first. The two orifices are near together. The internal characters of this Microscolex serve in great part to differentiate it from its allies, among which Microscolex longiseta is the nearest. The first septum divides segments iv.-v.; septa ix.-xii. are thickened. There is a moderately sized gizzard in segment v. The intestine seems to begin in xvii., but in longitudinal sections 1 cannot draw a line between it and the oesophagus. The latter is straight until the end of xi.; afterwards it is constricted by the septa. The sperm-sacs are in segment xi., as is so generally the case with the worms of this genus. The testes and funnels are in x. There is also a pair of sperm-sacs in ix., attached to the posterior wall of that segment and racemose, though containing little or no sperm. The single pair of spermathecae are in segment ix. Each is an oval pouch with a diverticulum as long as itself; the diverticulum is coiled in a spiral and ends in a swollen extremity. This is lined with a much-folded epithelium, so that the lumen appears to be divided by numerous radiating partitions. The most remarkable feature in the internal organization of the worm concerns the spermiducal glands. These are very long and of the usual tubular form. The entire efferent apparatus extends back to the xxviith segment, thus occupying ten segments. It measured 8 m m . in length. The spermiducal gland, however, did not reach so far back; but the muscular sac containing the penial setae passed beyond the end of the spermiducal gland. The latter is coiled slightly upon itself once or twice; it opens on to the exterior by a moderately short and narrow muscular duct. The sac containing the penial setae contained two of them, which were of such different lengths that one might speak of a dimorphism in the setae. One measured the full 8 mm., the other was not half its length. They were alike, however, in their form being without ornamentation at the free end. The sac contained an immature seta of a pale colour contrasting with the bright yellow of the mature seta, which was much longer than the smaller of the mature setae. The base of implantation of these penial setae was supplied with abundant blood-capillaries. The penial setae, the single sperm-duct, and the spermiducal gland open separately on to the exterior, though near together. (4) Microscolex michaelseni, n. sp. This is one of the most abundant species of Earthworms among the worms collected by Dr. Michaelsen. I have great pleasure in associating it with his name as a mark of m y respect for the valuable work which he has done in this department of natural history. The present species is a very well-marked form, and it is a matter of surprise to m e that it has never yet been described from |
