t?t5 SUilMABY OF CFKKEST RESEARCHES RELATISQ TO 



of subirenerti parallel vritli the cmstaeean genera on which they lire. The 

 anthers distinguish Gmpmon, Portunion, and Cancrion, and gire some 

 further notes ou the third of these. 



The study of the development of Enticyne is accompinied by many diffi- 

 culties ; it is certain that for a considerable time the embryos are free, and 

 during this period it is difficult to follow their metamorphoses ; they avoid 

 light, and it is therefore to be pi-esumed that crabs become infected during 

 the night. From what the authors have been able to see, they conclude 

 that the males of the different genen> pass through a Cryptonisous-stage. 



Development of Copepoda.* — M. F, Urbanowicz has investigated the 

 development of several species of Ci/clojps. The ovum undergi^es total seg- 

 mentation. One large sphere has its central extremity constricted off, to 

 form a central cell of unknown destiny. The result of segmentation is a 

 blastosphere containing nutritive yolk in the centnvl cavity. The external 

 cells divide radially and superficially. One specially large cell is inva- 

 ginated and multiplies to form the ectoderm cells, while the slightly 

 swollen internal extremities of ectoderm cells are constrict-ed off" to form 

 the primary mesoderm cells. A stomodteum is formed by invagination, a 

 mesoderm cleft forms the general cavity, and an endodermic cavity appears 

 as the mesenteron. Meanwhile the embryo elongates slightly ; the meso- 

 derm cells are grouped dorsally to form three pair of muscle-bundles for 

 the extremities ; while ventral and anterior dorsal ectodermic thickenings 

 form the ventral and dorsal ganglia, and apparently endodermic cells begin 

 to form the typical secondary mesoderm. 



When liberated, the larva exhibits no trace of segmentation, the two 

 portions of the nervous system are still unconne<?ted, the anus is not yet 

 formed, »ic. The appearance of the eye and kidney, and the development 

 of muscle from amaboid mesoderm cells are then noted. 



In the post-embryonic lite the mesoderm bands increase in length, and 

 the segments of the bcidy are formed. The body-cavity is enterocoelous. 

 The prootodfeum is evident in a hirva of thirty-six hours. In a nauplius 

 of twelve hours lateral ecto<iemiie thickenings rmite the anterior part of the 

 brain with the ventral ganglion, but the secondarv posterior portion of the 

 brain, bearing the eye, remains long separate. The growth of the double 

 ventral nerve-cord is then described. The kidney atrophies after hatching. 

 A pair of secondary kidneys appear in the second segment. The latter 

 probably correspond to segmental organs, the provisional kidney to the 

 analogous organ in the trochosphere larvae of Annelids. The genital cells 

 form an impaired organ towards the dorsal surface of the larva. The 

 ehell-secreting dorsal organ is then noted. 



Cypris and Melicerta.t — ^ilr. E. Eoberts records an attack which he 

 saw of a Cypris on a full-grown Melicerta ringens. The Cypris at first 

 seemed to be digging its claws into the bottom of the tube, as' if to tear it 

 from the leaf; then it climbed up and scratched one side for some time, 

 then the other, about half-way down, until there was a large hole in it. It 

 then went to the bottom of the tube, and whilst there the Melicerta came 

 out at the top and expanded its discs. The Cypris immediately climbed to 

 the top, and the Jlelicerta as suddenly disappeared ; and the former, with 

 its head down and its claws stretched out, began to scratch the middle 

 of the tube again, until part of it broke off;, leaving half the Melicerta 

 exposed. The Cypris then left it, and a number of minute, round, trans- 



* Kosmoe (Polish). 1885. Ct Arch. Slav, de Biol., L (1886) pp. 663-7. 

 t Sci.-Go6Bip, 1SS6, p. 2o9. 



