Studies on the Eyes of Arthropods Author:William Patten Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: STUDIES ON THE EYES OF ARTHROPODS. WILLIAM PATTEN, PH.D. 1. Development of the Eyes of Vespa, with Observations on the Ocelli of some Insects. In a former... more » paper (27) I gave an account of some observations on the structure of the compound eyes of Arthropods. Those observations, which were made almost entirely upon adult eyes, differed widely from those of recent writers on this subject. I desired to confirm, by embryological data, my observations on the continuity of the so-called rhabdom with the crystalline-cone cells, and on the nature of the corneagen.1 It was also important to determine whether there was any similarity between the development of the compound eyes and the ocelli. Moreover, if the opinion expressed in my former paper, that the primitive Arthropod eye was an invaginated and closed vesicle, be tenable, then it is necessary to show that the simplest Arthropod ocelli, which have heretofore been regarded as simple cup-like pits, are in reality closed vesicles. It is also necessary, in order to maintain my views on the origin of the compound eye, and the position and structure of the ommatidia, to show that the ommateum develops from the inner wall of the primitive optic vesicle. 1 The term " corneal hypodermis" employed in the paper referred to above is unsatisfactory on account of its length. In this paper I shall substitute corneagen for corneal hypodermis. Postscript. — Dr. Mark's memoir on " Simple Eyes in Arthropods," was received as this paper was going to the printer. He suggests " lentigen " to designate the layer of cells called by me corneagen. There are some considerations which make the word " lentigen " preferable to " corneagen; " but it seems to me they do not outweigh the objections which might be urged against it. It is important that th...« less