616 SUMMARY OF CURRENT RESEARCHES RELATING TO 



only two species have yet been described ; one was (1858) found by 

 Bruzelius in Pennatula rubra, the other by Claparede in Lobularia 

 digitata. The species now studied was found to change its form 

 incessantly during life, so that at one time it was cylindrical, and 

 at another rounded, and it might just as well as Claparede's species 

 have received the specific name of proteus ; a kind of soft parenchyma, 

 charged with globules, which are probably fatty in nature and are 

 coloured red, fills the body and renders it almost opaque. The 

 delicate chitinous membrane which envelopes the body presents no 

 trace of permanent annulation, but only temporary constrictions, 

 which correspond to any given state of contraction of the body. Of 

 the details of structure we can only say that, so far as the nervous 

 system is concerned, all that the author could discover was a small 

 refractive thickening near the eye, to which he is in doubt whether 

 or not he should apply the term of ganglion; the eye, itself, is 

 unpaired though double, and is to be found on the dorsal side a 

 little behind the rostrum. The nauplius-form was detected and some 

 of its characters were made out. 



This third species has been named Lamippe duthiersii. As 

 to its exact systematic position there would seem to be some not 

 inconsiderable doubt, but it certainly is Crustacean, and, owing to 

 the polymorphism exhibited by the parasitic Copepoda, we may for 

 the present regard the Lamippidse as forming a special division of 

 that group. 



The next subject discussed by Joliet is that of the functions of 

 the dorsal feet in the Notoproctous Crustacea. It is a well-known 

 fact that the Dromice, especially when young, hide themselves under 

 a kind of carapace, formed by a sponge or an alcyonium which they 

 hold on their back by the aid of their hinder feet, and he has 

 observed and here enters into full details with regard to the habits 

 of these Crustaceans ; he finds also that the Dorippidaa do the same 

 thing, and, though there is some difference in the anatomical structure 

 of these two sets of forms, there is no doubt that they have the same 

 habit of hiding themselves under various objects either to protect 

 themselves against their enemies, or to hide themselves from their 

 prey. 



Pontonia diazona n. sp., presents an instance of mimicry. The 

 Ascidian genus Diazona is very common at Mentone ; having placed 

 a small quantity of the masses formed by these creatures in clean 

 water, the author was, shortly afterwards, surprised to see a small 

 Crustacean swimming freely about. From a distance the animal could 

 only be detected by the movements that it made in the water, so com- 

 pletely transparent was it. Left to itself, it soon re-established itself 

 on the Diazona, where the transparent parts became so completely 

 confounded with the hyaline structures of the Ascidian, and the yellow 

 parts agreed so completely with the yellow markings of the colony, 

 that it was only by shaking or by previous knowledge that its exist- 

 ence could be detected. It was not possible to discover whether it 

 was a true parasite, or only a commensal, but its coloration and its 

 habits are sufficiently striking examples of mimetic action to justify 



