OCR Text |
Show 208 PROF. W. B. BENHAM ON AQUATIC [Nov. 3, penial sac. There is no atrial sac, and the atrium itself is not longer than the penis. In its general arrangement it resembles the apparatus in Hesperodrilus albus of Beddard. The spermathecce (one pair) extend through segments xiii. to xv.; the pore leads into a very slightly dilated muscular duct which soon becomes narrow and is much arched dorsally; on passing through the septum xiii./xiv. the duct, still narrow, becomes glandular, and then opens into the ampulla, which occupies the hinder part of segment xiv. and the whole of segment xv. Dimensions. 20 m m . x \ m m . 75 segments. Localities. Lakes Manapouri and Wakatipu, South Island of N e w Zealand. Remarks.-This worm agrees closely with those South-American worms for which the genus Hesperodrilus was founded by Mr. Beddard* ; but Dr. Michaelsent has shown good reason for merging this genus with Phreodrilus owing to the discovery, in Kerguelen, of a worm which in certain respects presents the characters of both the genera. The discovery in N e w Zealand of two new species, this and the following, belonging to the section of the genus hitherto found in the Falkland Islands, South America, and Kerguelen, is a most interesting additional fact in our knowledge of the geographical distribution of the Southern Oligocheeta. PHREODRILUS MAUIANUS+, sp. n. This new species is founded on a single immature individual, which, however, differs from any hitherto described. The ventral chsetse are, as usual, of two kinds, one of each in each bundle, viz.-{a) a simple hook-shaped, single-pointed bristle, and {b) a similar bristle with a very distinct tooth on its upper, convex, surface. These chaata? measure 0-15 mm., and are thus much longer than those of the species just described. The dorsal chsetse are capilliform, solitary, and commence in segment iii. The oesophagus is narrow up to segment vi., where it dilates, and is then constricted by the following septa. In the middle of segment ix. the gut presents a slight constriction, and the epithelium suddenly changes in its character-the oesophagus passing suddenly into the intestine. The dorsal vessel lies free of the gut in segment x. and forwards; a supra-intestinal vessel is recognisable in segments vii. to xv. An enlarged commissural vessel exists in segment x., and a contorted, swollen, heart-like organ in the following segment (xi.), which appears to be connected * Beddard, Ann. Mag. Nat. Hist. (ser. 6) xiii. p. 206; & Ergeb. Hamb. Magalhaen. Sammelreise, 1896-" Naid. Tubificid. u. Terricolen," p. 9. f Michaelsen, Oligoch. d. deutscb. Tiefsee Exped. 1902. X The specific name " mauianus" in which the syllable au has the sound of ow in cow, refers to the mythical Hercules of the Pacific, known to the Maoris as Maui. The North Island of N e w Zealand owes its origin to Maui, who, while fishing from a boat at sea, hauled up the land at the end of his fishing-line. Hence the original Maori name for this island was " Te ika a Maui "-the fish of Maui. |