A report on Penis and Baculum

Mallard pseudo-penis
Baculum of a dog's penis; the arrow shows the urethral sulcus.
Females have corkscrew vaginas with many blind pockets designed for difficult penetration and to prevent becoming pregnant. This reduced the likelihood of fertilization by unwanted aggressors in favor of fitter mates.
A raccoon baculum
External male genitalia of a Labrador Retriever
Walrus baculum, around 22 in long
Penises of minke whales on display at the Icelandic Phallological Museum
Genitorinary system of a raccoon (Procyon lotor)
Penis of a human, with pubic hair removed to show anatomical detail
The spine-covered penis of Callosobruchus analis, a bean weevil

The baculum (also penis bone, penile bone, or os penis, os genitale or os priapi ) is a bone found in the penis of many placental mammals.

- Baculum

A bone called the baculum or os penis is present in most mammals but absent in humans, cattle and horses.

- Penis
Mallard pseudo-penis

4 related topics with Alpha

Overall

A flaccid penis, with surrounding pubic hair removed to show anatomical detail

Human penis

2 links

External male intromittent organ that additionally serves as the urinal duct.

External male intromittent organ that additionally serves as the urinal duct.

A flaccid penis, with surrounding pubic hair removed to show anatomical detail
Lateral cross section of the penis
Anatomical diagram of a human penis
Various sized penises
Stages in the development of the male external genitalia
A urinating puer mingens by Annibale Carracci, 1600, Palazzo Farnese
The development of a penile erection, also showing the foreskin gradually retracting over the glans. 
''
See also: Commons image gallery''
A ventral view of a penis flaccid (left) and erect (middle); a dorsal view of a penis erect (right).
Hypospadias
Kanamara Matsuri festival in Japan
Papuan man wearing traditional penis sheath
A labelled dorsal view of a circumcised penis: (1) Shaft, (2) Circumcision scar, (3) Corona, (4) Glans, (5) Meatus.
Dissection showing the fascia of the penis as well as several surrounding structures
Image showing innervation and blood-supply of the human male external genitalia

The main parts are the root (radix); the body (corpus); and the epithelium of the penis including the shaft skin and the foreskin (prepuce) covering the glans penis.

The human penis differs from those of most other mammals, as it has no baculum (or erectile bone) and instead relies entirely on engorgement with blood to reach its erect state.

The internal anatomy of the human vulva, with the clitoral hood and labia minora indicated as lines. The clitoris extends from the visible portion to a point below the pubic bone.

Clitoris

2 links

Female sex organ present in mammals, ostriches and a limited number of other animals.

Female sex organ present in mammals, ostriches and a limited number of other animals.

The internal anatomy of the human vulva, with the clitoral hood and labia minora indicated as lines. The clitoris extends from the visible portion to a point below the pubic bone.
Stages in the development of the clitoris
Created by Helen O'Connell using MRI, the first 3D image of a clitoris in an erect state with the adjacent organs of the uterus and urinary bladder
Clitoris; deep dissection
A partially exposed clitoral glans, which can't be fully exposed due to a mild case of adhesions to the clitoral hood
Structures of the vulva, including external and internal parts of the clitoris
The clitoral hood has a normal anatomical variation in size and appearance in different adult women: while it is completely covered by the labia majora in some women, standing with their legs closed, in others it is pronounced and clearly visible.
Clitoral hood (1) and clitoris (2). Labia are spread apart on the bottom image.
An enlarged clitoris due to clitoromegaly
De re anatomica
A Georg Ludwig Kobelt illustration of the anatomy of the clitoris
Girl protesting for clitoris-awareness at a women's rights rally in Paris, 2019
With a urogenital system in which the female urinates, mates and gives birth via an enlarged, erectile clitoris, female spotted hyenas are the only female mammals devoid of an external vaginal opening.
Male and female reproductive systems of the spotted hyena, from Schmotzer & Zimmerman, Anatomischer Anzeiger (1922). Abb. 1 (Fig. 1.) Male reproductive anatomy. Abb. 2 (Fig. 2.) Female reproductive anatomy. Principal abbreviations (from Schmotzer & Zimmerman) are: T, testis; Vd, vas deferens; BU, urethral bulb; Ur, urethra; R, rectum; P, penis; S, scrotum; O, ovary; FT, tuba Fallopii; RL, ligament uteri; Ut, uterus; CC, Corpus clitoris. Remaining abbreviations, in alphabetical order, are: AG, parotid analis; B, vesica urinaria; CG, parotid Cowperi; CP, Corpus penis; CS, corpus spongiosum; GC, glans; GP, glans penis; LA, levator ani muscle; Pr, prepuce; RC, musculus retractor clitoris; RP, Musculus retractor penis; UCG, Canalis urogenital.

Unlike the penis, the male homologue (equivalent) to the clitoris, it usually does not contain the distal portion (or opening) of the urethra and is therefore not used for urination.

In females, this bone is known as the os clitoridis.

Three columns of erectile tissue make up most of the volume of the penis.

Erection

1 links

Three columns of erectile tissue make up most of the volume of the penis.
8 stages of erection
Various erection angle and shape of penises.
An erect horse penis

An erection (clinically: penile erection or penile tumescence) is a physiological phenomenon in which the penis becomes firm, engorged, and enlarged.

At the time of penetration, the canine penis is not erect, and only able to penetrate the female because it includes a narrow bone called the baculum, a feature of most placental mammals.

Fossa (animal)

1 links

Carnivorous mammal that is endemic to Madagascar.

Carnivorous mammal that is endemic to Madagascar.

The fossa has a cat-like appearance, resembling a small cougar.
Cranium (dorsal, ventral, and lateral views) and mandible (lateral and dorsal views)
External genitalia of Cryptoprocta ferox
Fossa are active both day and night (cathemeral).
Fossa illustration circa 1927

The male fossa has an unusually long penis and baculum (penis bone), reaching to between his forelegs when erect, with an average thickness of 20 mm. The glans extends about halfway down the shaft and is spiny except at the tip.

In comparison, the glans of felids is short and spiny, while that of viverrids is smooth and long.