No abstract

It is now well established that there are several species in the group of rough periwinkles inhabiting European rocky shores. The usual consensus agrees on four, namely Littorina saxatilis (Olivi), Littorina arcana Ellis, Littorina nigrolineata Gray and Littorina neglecta Bean. The first two species are particularly difficult to distinguish in the field and have received much attention. Recent work indicates that the ovoviviparous L.saxatilis is a very variable species living in a wide range of habitats (e.g. Janson, 1985) and that, although it is close to the oviparous L. arcana in shell morphology and in genotype, the two are separate species (Ward & Warwick, 1980; Ward & Janson, 1985), and not reproductive morphs of the same species.

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The musculature of the fore limbs and the innervation pattern of the muscles in the praying mantid Hierodula membranacea (Burm.) are described. There are three antagonistic pairs of muscles (promotors-remotors, abductors-adductors, anterior rotator-posterior rotators) operating the prothoracic-coxal joint around three different axes. At the coxo-trochanteral, femoro-tibial and tibio-tarsal joints there are flexor and extensor muscles, but at the tarsal-pretarsal joint only flexors are present. The trochanteral extensor is a complex muscle, with both parallel-fibred and pennate parts. The trochanteral-femoral joint is operated by a single muscle, the femoral reductor. There are six pairs of prothoracic nerves, the first of which innervates the musculature of the neck and pro-mesothoracic joints. The other five nerves are all concerned with the innervation of the muscles and sense organs of the prothoracic legs. Some of the motor neuron somata in the prothorathic ganglion have been identified by using the cobalt chloride backstaining technique. The leg musculature, its innervation pattern and the location of the motor neuron somata are compared with those of other orthopteroid insects.

No abstract