Tomigerus clausus
Encyclopedia
Tomigerus clausus is a species
of air-breathing land snail
, a terrestrial
pulmonate gastropod mollusk in the family Orthalicidae
.
The mantle is, with more highly thickened margins and more glandular epithelium than in Anostoma
, extends throughout the body whorl
of the shell to the region adjacent to the aperture
. It thus terminates at the point where the ureter
bends abruptly upon itself. The external openings of the ureter and intestine occupy the usual positions on the right side, and from this point pursue a course parallel to the external surface of the body in close contact with the mantle cavity. The ureter bends sharply upon itself at the termination of the mantle cavity, and, dorsally placed with reference to this chamber, proceeds anteriorly to unite with the forward extremity of the kidney. The body of kidney is a compact, sac-like body consisting, as usual, of highly folded glandular epithelium confined, in the posterior half of the organ, to the outer face. The pericardium
is in contact with this glandular section throughout its entire length, but is scarcely more than half as extensive. The no-pericardial opening was not observed. It may be added that the kidney is placed dorsally with reference to the pericardium.
There are no special features of the digestive system of Anostoma depressum.
The reproductive system, considering that the gonad is in a highly quiescent state, is comparatively large and more compact than in Anostoma. The gonad consists of several slender diverticula, located in the apical whorls of the visceral mass. These contain primitive sex cells undifferentiated into sperms and ova. The hermaphroditic duct extends ventrally, close to the columella, and shortly before entering the accessory glands attaches to a slender pear-shaped organ, possibly a seminal vesicle, consisting of upwards of ten small diverticula imbedded in a muscular sheath. These are empty and give no sign of glandular activity. The accessory glands are volummous, though inactive organs though several lobes give them a much greater dorso-ventral thickness. The duct leading from the accessory glands becomes considerably widened near its proximal extremity, and possibly functions as a shell gland. As in Anostoma, the duct from the seminal receptacle springs from this point, and, as a slender canal, proceeds to the spacious sack situated in close proximity to the accessory glands. The vas deferens
, likewise, unites with the penis some distance from its distal extremity, thus forming a flagellum. No penis retractor has been discovered in this region. On the other hand, several strands attaching to the penis sheath in the neighborhood of the outer opening may operate as retractors.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of air-breathing land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
, a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
pulmonate gastropod mollusk in the family Orthalicidae
Orthalicidae
Orthalicidae are a family of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks are classified in the informal group Sigmurethra of the clade Stylommatophora...
.
Anatomy
Anatomy of Tomigerus clausus was examined by Harold Heath in 1914.The mantle is, with more highly thickened margins and more glandular epithelium than in Anostoma
Anostoma
Anostoma, common name the up-mouth snails, is a genus of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the subfamily Bulimulinae, in the family Orthalicidae...
, extends throughout the body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
of the shell to the region adjacent to the aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
. It thus terminates at the point where the ureter
Ureter
In human anatomy, the ureters are muscular tubes that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long and ~3-4 mm in diameter....
bends abruptly upon itself. The external openings of the ureter and intestine occupy the usual positions on the right side, and from this point pursue a course parallel to the external surface of the body in close contact with the mantle cavity. The ureter bends sharply upon itself at the termination of the mantle cavity, and, dorsally placed with reference to this chamber, proceeds anteriorly to unite with the forward extremity of the kidney. The body of kidney is a compact, sac-like body consisting, as usual, of highly folded glandular epithelium confined, in the posterior half of the organ, to the outer face. The pericardium
Pericardium
The pericardium is a double-walled sac that contains the heart and the roots of the great vessels.-Layers:...
is in contact with this glandular section throughout its entire length, but is scarcely more than half as extensive. The no-pericardial opening was not observed. It may be added that the kidney is placed dorsally with reference to the pericardium.
There are no special features of the digestive system of Anostoma depressum.
The reproductive system, considering that the gonad is in a highly quiescent state, is comparatively large and more compact than in Anostoma. The gonad consists of several slender diverticula, located in the apical whorls of the visceral mass. These contain primitive sex cells undifferentiated into sperms and ova. The hermaphroditic duct extends ventrally, close to the columella, and shortly before entering the accessory glands attaches to a slender pear-shaped organ, possibly a seminal vesicle, consisting of upwards of ten small diverticula imbedded in a muscular sheath. These are empty and give no sign of glandular activity. The accessory glands are volummous, though inactive organs though several lobes give them a much greater dorso-ventral thickness. The duct leading from the accessory glands becomes considerably widened near its proximal extremity, and possibly functions as a shell gland. As in Anostoma, the duct from the seminal receptacle springs from this point, and, as a slender canal, proceeds to the spacious sack situated in close proximity to the accessory glands. The vas deferens
Vas deferens
The vas deferens , also called ductus deferens, , is part of the male anatomy of many vertebrates; they transport sperm from the epididymis in anticipation of ejaculation....
, likewise, unites with the penis some distance from its distal extremity, thus forming a flagellum. No penis retractor has been discovered in this region. On the other hand, several strands attaching to the penis sheath in the neighborhood of the outer opening may operate as retractors.