ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 85 



invaginated pit ; this fact proves that the compound eye is not to be 

 regarded as derived from coalesced ocelli ; similar observations have been 

 made by Sedgwick on Peripatus and by Locy on spiders, while Bobretzky 

 and Eeichenbach saw, but misunderstood the nature of, the pit. There is 

 nothing in the development of the eye of Crangon which warrants the 

 assumption that it or its stalk is an appendage homodynamous with the 

 other appendages. The author sides with Patten in his criticisms on 

 Grenacher's account of the structure of the eye of the adult Decapod ; he 

 thinks that the comparisons between the eyes of Arthropods and those of 

 Vertebrates " are not so absurd as they would have seemed a year ago." 



Crustacean Carapace.* — Dr. H. Ayers has recently t restated the theory 

 and collected the evidence that the carapace is not the fused terga of the 

 head and thorax, as it is usually stated to be, but that it is in reality the 

 coalesced terga of the antennal and mandibulary somites, and that the 

 " cervical suture," instead of being the line of separation between head and 

 thorax, indicates the junction of these somites. The " episterna " of Milne 

 Edwards are really portions of the sternum cut off by false sutures. 



Abnormal Limbs of Crustacea. J — Prof. E. Duns describes certain abnor- 

 malities in the thoracic appendages of Carcinus msenas, Cancer pagurus, and 

 Nephrops norvegicus. In the two former the abnormality consists of a bifid 

 or trifid character assumed by the terminal joint of one or more of the 

 appendages, more noticeably the chelsB ; accompanied in one case by an 

 elongation of the three terminal joints. In Nephrops, the protopodite of 

 the chela, which should be produced so as to form, with the dactylopodite, 

 a claw, is not so produced^ He considers it probable that these abnorma- 

 lities are due to the injury of the soft parts just after an ecdysis. It is 

 noteworthy that the mutilation occurs more often on the left than on the 

 right side. 



Mimonectes, a new genus of AmpMpoda Hyperidea.§ — Mr. C. Bovallius 

 remarks that the genus now described by him appears to afford the first 

 example of mimicry among the Amphipoda. The enormous globular 

 development of its body gives it a striking resemblance to a little jellyfish, 

 the straight slender legs and the minute tail hanging down as filaments. 

 The new family — Mimonectidee — to be formed for its reception, may be 

 defined as " Hyperids with the head and a part or the whole of the pereion 

 developed into an enormous balloon-shaped globe. Ocelli not united but 

 dispersed on each side of the head. The upper antennae long, more or 

 less straight ; the lower small, four-jointed. The mandibles without palp. 

 The maxillipeds well developed." The interior of the pereion forms 

 a bladder containing a fluid. Three species are described — M. Loveni, 

 M. sphsericus, and M. Steenstrupii — which were all found in the Atlantic. 

 Under the first form the author enters into full details of the anatomy, and 

 especially of the nervous system. 



The Genus Entione.|| — MM. A. Giard and J. Bonnier agree with 

 Kossmann in distinguishing the JBwfonzscMS-parasites of the PorcellanidjB 

 from those of the Crabs, to which the name Eniione should be applied. 

 Almost all the species of crabs found on the French coast seem to have a 

 special species of Entione, and these appear to be referable to a number 



* Amer. Natural., xx. (1886) p. 978. 



t Bull. Essex (U.S.A.) Inst., xvii. (1886) pp. 49-59 (2 pis.). 

 t Proc. R. Phys. Soc. Edin., ix. (1886) pp. 7.5-8 (1 pi.). 

 § Nova Acta Soc. Upsala, xiii. (1886) No. 4, 15 pp. (3 pis.). 

 II Comptes Eendus, ciii, (1886) pp. 645-7. 



