Term of Award

1975

Degree Name

Master of Science in Biology

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Committee Chair

James H. Oliver, Jr.

Committee Member 1

W. Keith Hartberg

Committee Member 2

Sturgis McKeever

Abstract

The anatomy and histology of the respiratory, nervous, reproductive, alimentary, excretory, and circulatory systems of adult male and female Antricola mexicanus Hoffmann are described. The respiratory system has a functional ostium which appears to be controlled by hemolymph pressure. No pores were seen in the spiracular plate, and six main tracheal trunks extend from the atrium. The nervous system consists of pre- and post-esophageal divisions. The preesophageal division contains the protocerebrum, cheliceral ganglia, pedipalpal ganglia, and stomodeal bridge. Paired nerves radiate from the protocerebrum, cheliceral ganglia, and pedipalpal ganglia while an unpaired nerve extends from the stomodeal bridge. The post-esophageal division contains four pair of pedal ganglia, a fused opisthosomal ganglion, and olfactory lobes which are specialized areas of the first pedal nerve neuropile. Pedal nerves extend from each pedal ganglion and branch to innervate the legs and body musculature. Paired opisthosomal nerves radiate from the opisthosomal ganglion, and the olfactory lobes receive axons which presumably arise from Haller's organ. Peripheral nerves extend from between adjacent pedal ganglia and from the area between the fourth pedal ganglion and the opisthosomal ganglion. In the male reproductive system, intercellular bridges were seen connecting adjacent primary spermatocytes in the testis. The bridges continued into the secondary spermatocyte stage. Asynchronous division occurs in the testicular cysts. The accessory gland consists of 12 granular and 2 spongy lobes. The spongy lobes also contained some secretory products. A previously unreported duct connects the accessory gland with the ejaculatory duct. In the female reproductive system, mature ova are found on the external surface of the posterior portion of the ovary and are connected to the lumen via tube-like passageways formed by cuboidal epithelial cells. No sperm were visible in the ovary. Sperm were observed inside the epithelial cells lining the ampulla, and brokendown sperm v/ere abundant in the lumen. One or two endospermatophores v/ere normally present in the uterus with eight being the largest number observed. The paired genital accessory glands open into the dorsal surface of the vestibular vagina. The alimentary system has no buccal cavity, and the labrum functions as a prepharyngeal valve. The salivary glands consist of nongranular (type I) and granular (type II) alveoli. One cell type was observed in both types of alveoli. Possible osmoregulatory roles are discussed. The midgut consists of a central pouch and seven pair of diverticula. Three cell types were present in the midgut epithelium. The connecting tube appears to have no digestive function. No rickettsiae were visible in the malpighian tubules. The paired coxal organs consist of a tubular, alveolar structure, a sacculus, and a duct leading to the external opening between coxae I and II. No cuticular structure supports the lumen of the alveolar structure, and the sacculus opens directly into the alveolar structure. One pair of ostia is present in the heart, and two types of hemocytes observed.

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