Fine structure and function of the coxal glands of lithobiomorph centipedes: Lithobius forficatus and L. crassipes (Chilopoda, Lithobiidae)

The ultrastructure of the coxal glands and associated tissues in the centipedes Lithobius forficatus and Lithobius crassipes has been examined in the light of two contrasting functional hypotheses postulated by different authors. Lithobiomorph chilopods possess eight sets of pores on the posterioventral border of the coxal podomeres of leg pairs 12-15 in adult (maturus) and subadult (pseudomaturus) stadia. A modified cuticular hypodermis, known as the coxal gland, surrounds the distal portion of each blindended pore. Each gland is made up of cells which contain large numbers of hypertrophied mitochondria and a highly folded apical and basal plasma membrane. The similarity of the coxal gland to so called "transporting epithelia" is discussed and further comparisons are made between these and secretory glands in arthropods. A careful consideration of both functional hypotheses (osmoregulation or pheromone release) has revealed the possibility that the coxal gland may encompass both functions.