772 Methods of Microscopical Research [Ocl ober , 



gland on the right side of the intestine, and that the stalks of 

 water weeds and other objects of which the nest is constructed, 

 are bound together by compound threads of six or eight fibers 

 spun by him in a fitful way as the material is secreted. 



The egg-membranes of floating fish ova, as those of Cybiuni 

 maculatum, are extremely thin, and pierced only by the micro- 

 pyle, not perforated by pore canals as is the case with ova, which 

 like those of the stickleback, salmon and shad, sink to the bottom. 

 The ova of C. maculatum, the Spanish mackerel, arc hatched in 

 twenty-four hours after fertilization, and the young are then in a 

 very rudimentary state. 



The gills of the so-called Lophobranchiates are not really 

 tufted, but the two series of vascular branchial appendages to 

 each arch in Hippocampus are homologous to the bifurcated vascu- 

 lar branchial appendages of a salmon or other fish. But these 

 appendages are much reduced in number, and, as if to compen- 

 sate for this, the area of the ultimate branchial lamellae or pinnae 

 ranged upon them is extended, and these leaflets increase in size 

 outwards, producing a tufted appearance. In all Lophobranchs 

 the branchial arches are reduced, the opercle is a simple plate, 

 the mouth is toothless, and the opercular membrane persistently 

 roofs over the gill chambers of the embryos. 



Experiments upon the retardation of the development of the 

 ova of the shad, with the end of ascertaining the possibility of 

 transporting them alive for long distances, were not successful on 

 account of the development of fungus, but in four and a half days 

 the ova at a temperature of 5 2° R, had not advanced farther than 

 they would have done in water at 8o° in twenty-four hours. 



METHODS OF MICROSCOPICAL RESEARCH IN THE 

 ZOOLOGICAL STATION IN NAPLES. 



(Continued ' jrom September number.) 

 II. Stain- in.; Methods. 

 TT has gradually become a settled custom in the Zoologi 

 •*• tion, to mount microscopical preparations in balsam v 

 this can be successfully done ; and to avoid, as much as p 

 the use of aqueous media, both in mounting and stainim 

 disadvantages often arising from the use of these media i 



