They end mainly on the dendritic spines of the spiny neurons. Spore surfaces may be hairy, rugose, smooth, spiny or warty. Bottom trawlers and sink gillnets are the primary equipment used to harvest spiny dogfish. Recreational fishing accounts for an insignificant portion of the spiny dogfish harvest. The rostellum is armed with two rows of chitinous spiny hooks. The mosaic is made of pieces of turquoise, spiny oyster shell and conch shell. These are annual and perennial herbs with hairless and usually spiny leaves. They are either lobate or pinnate, with spiny edges. It is a member of the genus "Sceloporus" (the spiny lizards). Echinoderms (Greek for "spiny skin") is a phylum which contains only marine invertebrates. A few species can creep very slowly by using spiny defensive zooids as legs. Despite being called "spiny sharks," acanthodians predate sharks. Metabotropic dopamine receptors are present both on spiny neurons and on cortical axon terminals. The pistillate heads consist of two pistillate flowers surrounded by a spiny involucre. The striatum is composed mostly of medium spiny neurons.