6926475848

170

Arquivos de Zoologia

mass posteriorly situated, almost outside of snout; around mouth aperture a very strong, thick layered circular muscle. Jaws in two tapered plates in dorsal wali of buccal mass, just where 2 strong, broad, tali parallel and longitudinal folds begin, run in dorsal inner surface posteriorly; in anterior esophagus right fold gradually faints, left fold con-tinues in middle esophagus (fig. 307). Odontophore similar to those of preceding species, with following distinctive characters (figs 310-313): 1) radular ribbon short; 2) m8 very short, broad, with almost same width than radula; 3) mil pair originating in posterior region of inner surface of subradular membranę (near radula), runs anterioriy with smali connection in m7 and large connection in peribuccal wali; 4) a pair of smali and narrow muscles originating in median-dorsal region of m4 and running ventrally as part of m7; 5) m7 with four components inorigin (two from mil and two from m4), and 3 connected diverticles from radular sac; 6) mlO posteriorly inserted, near m4; 7) ligament of radular sac with inner-anterior surface of horizontal muscle; 8) horizontal muscle (m6) long, almost same length than cartilages. Radular teeth (figs 98, 99): rachidian with sornewhat rounded outline, with 5 cusps being central cusp larger (about double); lateral tooth with 4 or 5 cusps, second cup larger; marginal teeth spoon-like, with rounded terminal cusps, inner and outer marginal teeth very similar with each other. Both salivary glands extend through nerve ring, bearing glandu-lar tissue anterior and posterior to it (fig. 308). Esophagus broad and complex (figs 307-309). A tali fold initiated in inner dorsal wali of buccal mass, divides dorsally anterior and middle esophagus in two broad pouches, right pouch longei; both generally with several oblique, uniform folds, but some variation occurs, these folds can be, in some specimens, longitudinal or concentric; separating ventrally each pouch a space with nonę, or up to three marrow and Iow longitudinal folds. Tali dorsal fold, in some specimens, with a deep median furrow in its middle region, being practically a third short pouch, intemally some longitudinal Iow folds. Posterior esophagus a simple tubę with smooth inner surface. Stornach (figs 304, 305) large; well developed folded dorsal sorting area; central pad-like fold smali, flattened and thin; aperture of esophagus and digestive gland as showing in fig. 304, at left of this fold; short smooth chamber preceding aperture of style sac and intestine. Style! sac long, with style, separated from intestine.* -Intestine origin close to style sac aperture, dorsall to it, contours lefl-ventral side of style sac, with I single loop return to anterior; in right posterior limit I of pallial cavity suddenly expands becoming veryl wide rectum with compacted fecal pellets obliquely i disposed. Anus siphoned, posterior situated int cavity (fig. 302). Digestive gland begins in middle- [ ventral region of stornach and runs posteriorly two | whorls morę. Other details of digestive system in| Houbrick (1980a: 124-127).

Genital system. Małe (figs 302,305, 306). Testis in several lobes dispersed in ventxal and outer regions of digestive gland and stornach, touching kidney when developed. Vas deferens white, broad, with thick walls, running close columella; several consecutive secondary branches, each one coming from a lobe; between rectum and right posterior limit of pallia! cavity, vas deferens opens, becoming a simple groove with thick glandular walls.

Female. Pallial oviduct very similar to that figured by Houbrick (I980a:130, fig. 8b), a smali posterior region closed occurs in examined specimens; bursa and receptacle have a larger j closure degree. Other details of genital system in Houbrick (1980a: 127-131). Ovopositor (fig. 299) j a bulbous, swollen flap with thick glandular walls i and a central longitudinal furrow (see Houbrick,

1980a: 121, fig. 2b). Female MZSP 24995 presents two spermatophores within pallial oviduct, vcry similar to that described by Houbrick (1980a: 128, figs. a-b).

Measurements (in mm). MZSP 28258: 12.0 by 13.1; 10.1 by 13.0, 8.9 by 10.8; MZSP 28257: 8.3 by 11.2 (figured specimen); 14.7 by 13.7).

Distribution. From Florida, USA to Santa Catarina, Brazil.

Habitat. Intertidal or upper infratidal rocks, moving on algae, in regions with waves of Iow eneigy.

Materiał examined. Vcnezuela; Nova Esparta; Margarita Island, Porlamar, Guaraguao Bay, Vella Vista beach, 6 specimens, MZSP 28257 (Simone col. 6/ii/l 995). Brazil; Alagoas; Maceió, Sete Coąueiros Beach, 1 specimen, MZSP 24992 (Montouchet col., 19/ix/1970); Rio de Janeiro; Cabo Frio, Conchas Beach, ! specimen, MZSP 24995 (Marini col., 6/i/l 973); Sao Paulo; Ilha Bela, Central beach, 48 specimens, MZSP 28258 (Simone col., v/l994);BarraVelha, 1 specimen observed