On our Present Knowledge of the Gregarinidæ, with Descriptions of Three New Species belonging to that class

In Vol. I. of this Journal (1853), p. 211, an abstract appeared of some observations made by Kölliker and others on the Gregarinidæ, a group of animals of very simple structure, met with in the intestine and other parts of many insects and annelids, the nature of which was then, and is still, a matter of considerable interest to naturalists. Others have worked at the subject since that time, but little has. been published in England relating to these parasites, nor are they generally known to microscopic observers in this country. It may, therefore, be advantageous to give in a condensed form what is known of their structure and development, adding a list of species and a few original observations.