Although the exact process of egg mass formation is unknown, the most accepted hypothesis suggests that, at spawning, eggs are first coated with oviducal gland secretion and released with nidamental gland
The red accessory nidamental gland
occurred more than 10 times during the entire video footage (Table 3), usually during the daytime, when the females positioned themselves parallel to the males.
Males were defined as those whelk with a penis, and females were defined as those whelk with a nidamental gland
. Scissors were used to separate the gonad from the digestive gland (gonads were not weighed).
Structure and function of the nidamental gland
of Chyloscyllium grisseum (Muller and Henle).
The sexual maturity stages were determined using the measurements of reproductive organs quoted for this species (Robaina & Voglar 1986, Voglar & Robaina 1987), and the female sexual maturity stages were estimated using the nidamental gland
index (NGI = (Nidamental Gland
length/Dorsal Mantle length)) (Durward et al.
It was described for females as (1) immature (stage 1): short and translucid nidamental gland
and transparent ovary; (2) maturation (stage 2): cream nidamental glands
and granulated ovary; (3) mature (stage 3): larger nidamental glands
(20%-50% of the mantle cavity) and ovary full of eggs, yellow colored; and (4) spawned (stage 4): flaccid and reduced nidamental glands
and oviduct with some eggs.
Behavioral responses to natural eggs were compared with responses to artificial egg capsules coated with extracts (4) from one of four female reproductive organs or glands: ovary, oviducal gland, nidamental gland
, or accessory nidamental gland
After recording the total body weight (TW), each specimen was dissected to separate different organs and the following measurements of weight were recorded in grams: mantle weight (MW); head weight, including arms and tentacles (HW); viscera weight, including gills, stomach, cecum, hepatopancreas, and ink sac (VW); ovary weight, including oviduct and oviducal gland (OW); testis weight (TW); and nidamental gland
A high incidence of infection (47%) was noted in the reproductive organs (nidamental gland
, accessory nidamental gland
, and gonads).
There was a negative correlation between Gonado Somatic Index and Nidamental gland
Somatic Index and each of total protein and lipids in different sexes (P = 0.01), which was not the case with total carbohydrates (P = 0.1).
Internal organs, such as the red accessory nidamental gland
in females, are often visible.
So that females could be selected, the gonad at the anterior end of the mantle cavity was first examined in thin sections by light microscopy; if it was judged to be an ovary, the sectioning was continued until the region of accessory nidamental gland