HAEFNER: REPRODUCTIVE BIOLOGY OFGERYONQUINQUEDENS 



Very Early Development 



In very early development (Table 1 ), the ovary is 

 small ( <0.2 ml in volume; horn width 0.5 mm) and 

 colorless. A central lumen is not apparent from 

 gross morphological examination, although the 

 precursor of one is indicated in Figure 2. Lobation 

 is not obvious in this stage. The bulk of the organ 

 consists of fibrous connective tissue, apparently 

 stratified, and blood sinuses (Figure 2A). The 

 outer connective tissue wall of the ovary is not 

 readily distinguishable from the inner connective 

 tissue. Various cell types are present. Most cells 

 contain one oval nucleus (7.2 fim long) while other 

 larger, less numerous cells have a large round 

 nucleus (7.2 /xm in diameter). Ova diameters are 

 small (40-172 /xm) and confined to germinative 

 areas or strands. In some instances, it is difficult to 

 free the ova from the surrounding tissue even after 

 treatment in Gilson's fluid. The germinal zone 

 consists of columnar cells with (12 /xm) elongate 

 nuclei (Figure 2B). 



throughout the ovary. Cells in an early stage of 

 oogenesis, recognizable by vacuolate nuclei (Fig- 

 ure 3B), are small (14-53 /urn) compared with the 

 more advanced ova (74-278 /xm) characterized by 

 more compact nuclei and the presence of 

 cytoplasmic yolk granules (Figure 3C, D). They 

 are surrounded by a single layer of follicular cells 

 (Figure 3D) which are spindle shaped with an 

 elongate nucleus (72 /xm). 



Intermediate Stage 



As the ovary progresses to the intermediate 

 stage of development, accumulating yolk, it 

 gradually occupies more space (G, = 1.4-2.7) in the 

 visceral cavity and changes color (Table 1). The 

 ovarian architecture is little changed from that of 

 earlier stages; connective tissue is confined to the 

 margin of the ovary and to the interstices between 

 the now obvious lobes. Germinative zones are 

 present. Ova are larger (1 12-537 /xm) than those in 

 earlier stages. 



Early Development 



White, ivory, light gray, or light yellow ovaries 

 which are small (0.2-2.0 ml volume, 2-6 mm horn 

 width) may exhibit histological development in 

 advance of the previous stage. Most of the organ is 

 filled with ova in various early stages of de- 

 velopment (Figure 3A). Connective tissue is still 

 prevalent around the margin, penetrating the 

 ovary in numerous locations to form small lobes 

 which are not readily visible from a gross mor- 

 phological aspect. 



The germinal zone is well defined and branches 



Mature Stages 



A fully mature ovary nearly obscures the 

 hepatopancreas in dorsal view. Only a small por- 

 tion of the hepatopancreas and the slightly coiled 

 midgut caecae are visible between the ovary and 

 branchial chamber (Figure 1). The high gonad 

 indices (>2. 7) attest to the large volume (8-32 ml) 

 of the organ at these stages of development. The 

 color remains variable but is generally darker 

 than that of earlier stages as reddish and brownish 

 hues become evident (Table 1). 



The predominant histological feature in a 



TABLE 1. — Descriptive stages of Geryon quinquedens ovary: color variation, horn size, volume, gonad index, and ova diameter. 



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