*Phylum Nematoda consists completely of Roundworms. *Two types: parasitic and free-living. 90,000 species known; many more exist! *These Roundworms are unsegmented; they have long, narrow, cylindrical bodies that taper to a fine tip in the posterior and a blunt end at the head. Also, they have a cuticle--a tough layer of outerskin--covering their entire bodies. *They are pseudocoelomates. They have a pseudocoelom, an internal body space surrounding the endoderm tissue of the digestive tract and surrounded …
showed first 75 words of 208 total

showed last 75 words of 208 total
…words, Roundworms are cooler than Flatworms]. *Longitudinal muscles; they move side-to-side in a thrash-like motion. *Reproduce sexually. Fertilization = internal, and females deposit more than 100,000 fertilized eggs per day. Zygotes can survive harsh conditions. *Many live in moist soil and in organic matter on the bottoms of lakes and oceans. Play an important role in decomposition and nutrient cycling. *Closely related to phylum Rotifera; they are both VERY small (microscopic) and have a complete digestive tract.