Although there are no confirmed fossil records of mollusc parasitic nematodes, diverse associations of more than 108 described nematode species with slugs and snails provide a fertile ground for speculation of how mollusc parasitism evolved in nematodes. Current phylogenic resolution suggests that molluscs have been independently acquired as hosts on a number of occasions. However, molluscs are...

*Research aided by grant (G-199) and summer Travel Fellowship (1957) from the National Council to Combat Blindness, Inc., and in part from the United States Public Health Service, Institute of Neurological Diseases and Blindness (B-397). Received for publ~catlon, July 7, 1958. chemical study of photoreceptors in our laboratory (1-5). The invertebrate photoreceptors have recently been reviewed b...

Anabarella , a conspicuous taxon of early mollusc, is widely distributed in the Cambrian strata and considered an important link evolutionary lineage that reflects transitional form from helcionelloids to bivalves. In South China, has mainly been documented Yunnan, Shaanxi, Sichuan, Hubei provinces. However, taxonomy questionable, which implications for interpretation genus’ temporal spatial di...

Introduction Conclusions References

The polypeptide chain composition and the chemical properties of several annelid hemoglobins and chlorocruorins are presented. In agreement with earlier studies on the hemoglobin from Arenicola cristata (Waxman, L. (1971) J. Biol. Chem. 246, 7318-7327), nearly all of the pigments which have been examined consist of one or more different disulfide-linked polypeptide chains of 13,000 to 16,000 da...