1. The development of the ascocarp in Cudonia lutea and in Spathularia velutipes is notable for the appearance of an inclosing membrane which covers over the entire fructification, and which constitutes a morphologically distinct organ of the fruit body. Very early stages of Cudonia show its presence, and it is one of the first organs of the ascocarp to be differentiated. Trichoglossum hirsutum lacks entirely any such investment, and the ascocarp is therefore gymnocarpous. Leotia lubrica shows some evidences of possessing an evanescent veil, but this is a point which requires further elucidation. 2. The value of the Helvellinean veil as a systematic criterion depends more upon the fact that it is a morphologically distinct organ inclosing the entire ascocarp than that it may result in an endogenous development of the hymenium. This being so, the closest homology to the Helvellinean veil is to be found, not in the Pezizineae, but in the Baeomyces group of the disco-lichens. This is adduced as evidence of relationship between these groups. 3. The fertile systems of Cudonia lutea and Spathularia velutipes appear at an early stage in the history of the fructification as threads which have been called "generative hyphae." These hyphae proliferate with the other tissues of the ascocarp, and at a later stage give rise to the procarps. The procarps of Cudonia are irregularly coiled, and are provided with multiseptate trichogynes which pass outward and protrude through the veil. The nuclear history is not fully known, but the original condition of the cells of the procarp seems to be uninucleate, later becoming multinucleate, and at this stage giving evidence of nuclear pairing. Ascogenous hyphae arise from the cells of the procarps, after which the procarps become emptied of their contents and finally disappear. The procarps of Spathularia appear somewhat later than in Cudonia, and are formed close to the hymenium. They are irregular, do not possess trichogynes, and are obviously reduced in structure. They are multinucleate throughout their history, and the nuclei are paired. Ascogenous hyphae arise from them. 4. In Trichoglossum hirsutum there is no structural differentiation of sex organs. The ascogenous hyphae arise from threads which do not differ in form from vegetative ones. 5. In Leotia lubrica bodies resembling in some respects the "storage bodies" described by Brown for the same form were found to produce ascogenous hyphae. On this account it is suggested that they may represent sex organs, that is, they may be degenerate procarps. 6. It is pointed out that there is a very close correspondence in the history of the fertile systems of the Geoglossaceae and of certain disco-lichens of the Baeomyces group. This is cited as further evidence of relationship between them. 7. It is suggested that the progress of evolution in these plants has been from a type in which fertilization took place through the agency of the trichogyne, and has been marked by gradual reduction of the sex organs.