Everettia jucunda (Pfeiffer, 1863)
“This shell was placed by von Martens in the genus Macrochlamys; and looking at its shiny glassy shell, so very like many in the Indian region, I should certainly have done the same; yet the animal differs from that genus not in one but in several characters – externally in the absence of the long shell-lobes; internally in the odontophore and jaw; and in the reproductive organs it is widely separable, Macrochlamys not possessing the spicula amoris. In searching through Semper's work for characters approaching those now figured and described, I observe the nearest, as might be expected, in those genera found in the islands of the Malay Archipelago and not in those found to the westward in India. On plate iii. figs. 1, 2, Reise im Archipel d. Philipp., is shown the sagitta amatoria of Tennentia philippinensis and Parmarion pupillaris, from Java, of the same type. This I would submit is an indication that the sluglike forms of this part of the world are the descendants of these glassy Helices, just as we find the general anatomy of Girasia, a slug-like species of India, to be like that of Macrochlamys, and that although the outward form of both animal and shell is very similar respectively, the races of the two areas have a most remote relationship. How far these characters of Everettia and Dyakia extend around this area is yet to be discovered. We cannot as yet say with certainty that shells with similar internal structure do not exist in India; they are certainly absent in the N.E. Himalayas and Khasi Hill Ranges, but there are numbers of even large species in Southern India yet to be examined, and of which we know as yet nothing. Of the shells of New Guinea we are also quite ignorant; at least I have not seen any work on their anatomical variations.” (Godwin-Austen, 1891)
“The figure given by Martens (Preuss. Exped. Ost-Asien, Zool. Bd. ii. Pl. xii. Fig. 7) appears to represent this species, although on close examination it is seen to consist of about one whorl less than the type; but perfect accuracy in a matter of this kind is not to be expected from the average artist.” (E. A. Smith, 1895)
“Remarks: The size of the specimens from Brunei is greater than the Beaufort and Pulau Tiga specimens. The type was described from Labuan Island, which is located at the centre of its known distribution range.” (Liew et al., 2009)
Pfeiffer (1863) original descriptions on Helix jucunda – “T. subclause perforata, conoideo-depressa, tenuis, sub lente conferte striata, nitida, fuscocornea; spira breviter conoideo-elevata, vertice subtili; anfr. 6½, convexiusculi, lente accrescentes, ultimus non descendens, peripheria rotundatus, basi medio impressus; apertura vix obliqua, irregulariter lunaris, intus submargaritacea; perist. simplex, rectum, marginibus distantibus, dextro regulariter arcuato, columellari declivi, parum arcuato, ad insertionem breviter refiexo.”
Tryon (1886) descriptions on Nanina (Macrochlamys) jucunda – “Perforation nearly covered, thin, lightly striatulate, shining; brownish corneous; whorls 6½, periphery rounded."
Liew et al. (2009) descriptions on Everettia jucunda – “medium-sized, rather thin, brownish, moderately elevated, outer whorls rounded. Periphery rounded. Above the periphery, shell shiny with a regularly and densely placed spiral striation, c. 30–40 per mm. Below the periphery, shell has fine, densely placed spiral grooves. …number of whorls up to six and three-quarters…”
“The animal from a spirit-specimen is pale ochre in colour, with jet black tentacles and a black band on either side of the neck from the base of the tentacles running backwards. The pallial margin is broad, the foot below with a central ambulatory area. The mucous gland is large, and in life the extremity of the foot is apparently much pointed and overhanging. There are no linguiform shell-lobes either on the right or left side, but on the latter the lobe is a simple baud turned back over the edge of the peristome; both the right and left neck-lobes are very small.” (Godwin-Austen, 1891)
“Animal: black bands on either side of tentacles, which are divided by a white band occupying the space between eye tentacles, and extended backward to the end of mantle and downward to just below the eye tentacles. Grey smear on either side of the tail extending from the umbilicus region to the end of the tail. Other parts of the animal are devoid of any markings. The mantle is covered by brown irregular markings and followed by regularly spaced radial darker brown bands at the last half whorl.” (Liew et al., 2009)
“The generative organs are very peculiar and unlike those of any species I have examined or that I find figured by Professor Semper. The principal difference lies in the amatorial organ or dart-sac; this is cylindrical below as in other genera, but at the inner extremity terminates in a fringe of very numerous accessory glands, very nearly equal in length to the solid fleshy lower portion. These fringe-like glands are finely pointed and lie buried in a mass of mucous glands having a segmented structure, each separate lobe being associated with one of the accessory glands. The lower end is armed with a stout and solid calcareous dart (Liebespiel), having a conical attachment to the muscular portion. The penis has no kale-sac. The albumen-gland is very large.” (Godwin-Austen, 1891)
“The odontophore :-The rows of teeth, about 90, gradually decrease to the outer margin, the formula being (30. 26. 1. 26. 30.) & (56. 1. 56.). The central tooth is much shorter and smaller than the laterals, and is tricuspid, the two outer cusps being just below the centre point; in one specimen dissected, owing to the central part being much worn, this central tooth is evenly tricuspid. The laterals rise from long narrow plates, and are very pointed, with an outer and inner cusp some distance below the apex, being thus also tricuspid; the outermost laterals are very nearly unicuspid. The jaw is curved, but has no central projection.” (Godwin-Austen, 1891)
“Genitalia: maximum length from genital opening to the end of dart-sac (before the visible gland tubules) up to c. 13 mm. Penis, vagina, genital opening, bursa copulatrix, and dart-sac arranged around the short genital atrium, with limited space between the opening of each of the genital structures. Long bursa copulatrix almost same length as dart-sac.” (Liew et al., 2009)
Helix jucunda – “Diam. maj. 17, min. 15½, alt. 9 mill.” (Pfeiffer, 1863); Nanina (Macrochlamys) jucunda – “Diam. 17, alt. 9 mill.” (Tryon, 1886); Everettia jucunda – “The specimen figured measures: maj. diam. 19.0, min. 18.5; alt. axis 9.0 millim.” (Godwin-Austen, 1891); Everettia jucunda – “Height up to 10.5 mm; width up to 17.3 mm; diameter of the first three whorls 0.8–0.9, 0.6–0.7, and 0.8–0.9 mm, respectively; height aperture up to 7.7 mm; width aperture up to 9.8 mm.” (Liew et al., 2009)
Shell height – 9 mm; Shell width – 15-17 mm.
Type locality – “insula Labuan” leg. H. Low (Pfeiffer, 1863)
Other localities – “Territorio di Sarawak” leg. Doria and Beccari (Issel, 1874); “Tiga Island” leg. A. Everett (E. A. Smith, 1895); ”Baram in Sarawak” leg. C. Hose (E. A. Smith, 1895); “Baram” leg. Kükenthal (Kobelt, 1897); “Sabah; Tiga Islands” (Liew et al., 2009); “Sabah; Beaufort, Kuala Penyu” (Liew et al., 2009); “Sabah; Sipitang, Sipitang Beach” (Liew et al., 2009); “Brunei: Labi Waterfall” leg. Vermeulen/2003 (Liew et al., 2009)
Primary forest and peat swamp forest. Sabah: Pulau Tiga, Beaufort, Klias Forest Reserve
“Distribution; Sabah: Pulau Tiga, Beaufort, Klias Forest Reserve.” (Liew et al., 2009)
“Habitat: Primary forest and peat swamp forest.” (Liew et al., 2009)