650 RECORD OP CURRENT RESEARCHES RELATING TO 



other Siplionophoro ; commencing as a bud on the ciliated base of the 

 feeding polyp, it is at first only composed of an ectoderm and cndo- 

 derm. The ectodermic wall divides into two layers and gives rise 

 to the involucrum ; within this the sacciilns becomes coiled np, and 

 shortly appears as a complicated organ armed with lasso-cells ; mean- 

 while the basal jjortion becomes so enlarged as to give an asymmetrical 

 form to the whole knob. As the fully grown stage is reached, this 

 enlargement forms a simjile tube along the side of the knob, and tho 

 complete condition is arrived at. It is interesting to note that in some 

 allied genera we find arrangements of the parts of the knob which 

 are only temjjorary in the species under description. 



The mantle-tubes of Apolemia uvaria and Gleha h'ppopus are also 

 described, and the tubes in the larger necto-calyx of Abyla pentagona ; 

 he adds some critical remarks on the genera Halistemma, Agalma, and 

 Agalmopsis, and concludes with a notice of the forms of Siphonophora 

 and VelellidiB to be met with on the eastern coast of the United 

 States. 



Up to the present few forms of either of these groups have been 

 described from American waters. They seem to be only occasional 

 visitors blown into the neighbourhood from mid-ocean, and brought 

 there from the tropics by the Gulf Stream. The wealth of such 

 species that one meets with in the Mediterranean is unknown on the 

 New England coast; while, as the author says, in one day at Nice he 

 has taken eight different genera of Siphonophora, yet at Newport he 

 has but rarely taken as many as two genera in the length of a 

 summer's day, and a whole summer once passed, during most of which 

 he was almost daily on the water without one species being seen. 

 One or two species of Phijsalia are, however, more common on the 

 United States coasts than in the Mediterranean. 



The only member of the long-stemmed Siphonophora provided 

 with a float or air-bladder found heretofore on the New England 

 waters is Agalmopsis cara. Mr. Fewkes can now add A. elegans, and 

 he thinks that extended observation in the southern bays of the 

 country will bring to light some of the well-known forms common to 

 all oceans, such as Apolemia, Ahyla, Phijsophora, and Gleha. Some of 

 these have already been taken in the Gulf of Mexico and the 

 Caribbean Sea. Bhizophysa, found in the same localities, might also 

 be expected to be brought to Eastern American coasts by oceanic 

 currents. 



Origin and Development of the Ovum in Eucope before Fecunda- 

 tion.* — This subject has been studied by C. Merejkowsky, who gives 

 the following as the results of his researches. The ovaries of the 

 Medusa, in the interior of the bell, have the appearance of four small 

 sacs, due to an evagination of the gastro-vascular cavity. In the 

 walls of the ovaries, from without inwards we find a layer of 

 ectodermic cells, the limits of which are not well defined, and the 

 entoderm composed of several layers of better defined cells. Tho 

 innermost layer of the entoderm, that which covers the inner surfiice 



* ' Comptes Remliit^,' xc. (1880) p. 1012. 



