1887.] 



PROF. HOWES ON PALINURUS PENICILLATUS. 



4G9 



faceted inner free border, and that it had all the characters and 

 relations of an endopodite. 



If this were so, and if the homologj^ between a typical appendage 

 and the eye-stalk was accepted, the eye-bearing (corneal) })ortion 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 '. 



Cephalon of Falinurus 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 theoreliques relatives a la 

 similitude fondamentale des parties susceptibles de revetir des 

 caracteres diffe'rentes " "-. 



' 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. EoUeston had cited it as an example " of the occasional 

 replacement of their facets by a flageUum such as the antennse carry." This, 

 Prof. Howes had ascertained from M. Milne-Edwards, was a misinterpretation 

 of the original description, the cornea and flagellum being, in reality, discon- 

 tinuous. 



^ The ' Challenger ' Reports have recently brought to light the following. 

 Sars has shown that, among the Schizopods, liighly organized luminous organs 

 appear (ex. Euphasia) at the bases of certain appendages and elsewhere ; con- 

 cerning those of the appendages, it is significant to find that tliey 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, Astrvrus, and Munna a condition essentially intermediate between 

 the typically Edriophthalmous and Podophthalmous types.— G. B. H. 



