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Show 1887.] PROF. HOWES ON PALINURUS PENICILLATUS. 469 faceted inner free border, and that it had all the characters and relations of an endopodite. If this were so, and if the homology between a typical appendage and the eye-stalk was accepted, the eye-bearing (corneal) portion was clearly exopoditic in position, and it became a question as to how far it might, or might not, represent that segment of the typical appendage 1. Cephalon of Palinurus penicillatus, bearing an antenniform ophthalmite. Prof. Howes held that the only logical conclusion which could be drawn from the study of the specimen was that it supported what M. Milne-Edwards tersely calls, " les vues theoretiques relatives a. la similitude fondamentale des parties susceptibles de revetir des caracteres differentes"2. 1 The only reference to this specimen made by subsequent writers was one by Rolleston in his remarkable work ' Forms of Animal Life.' Dealing with the eyes of Crustacea, Prof. Rolleston had cited it as an example " of the occasional replacement of their facets by a flagellum such as the antenna? carry." This, Prof. Howes had ascertained from M . Milne-Edwards, was a misinterpretation of the original description, the cornea and flagellum being, in reality, discontinuous. 2 The ' Challenger'Reports have recently brought to light the following. Sars has shown that, among the Schizopods, highly organized luminous organs appear (ex. Euphasia) at the bases of certain appendages and elsewhere; concerning those of the appendages, it is significant to find that they are borne upon the eye-stalks in addition to the true visual organs, and that in a position identical with those of the post-oral series. Beddard records in the Isopods Arcturus, Astrurus, and Munna a condition essentially intermediate between the typicallv Edriophthalmous and Podophthalmous types.-G. B. H . |
