448 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



them down. If the eggs were too young, the tish was put back in run- 

 nfng water and examined again later, although it rarely survived a 

 second operation unless the eggs were newly laid and hence came out 

 easily. This is a wasteful process, since many eggs are spoiled in 

 removing them. The obtaining of a series of eggs and embr3^os of 

 Sip/iostoma is a long, slow, and laborious task and is quite as much 

 the result of chance as of skill and knowledge. 



A variety of killing fluids has been used. The oil drops under the 

 germ disk were so blackened by osmic acid and Flemming's fluid that 

 these reagents could not be used. Acetic alcohol, Kleinenberg, 

 sublimate-acetic, picro-acetic, all gave good blastoderms, but the yolks 

 generall}^ went to pieces. Excellent results were obtained with fresh 

 Perenyi, 10 per cent, and 20 per cent formalin, and, for later stages, 

 Gilson's and Worcester's fluids. This latter is one of the best fluids 

 for killing teleostean eggs with which I am acquainted. It is composed 

 of saturated sublimate in 10 percent formalin, 90 parts; glacial acetic, 

 10 parts. The eggs are left in this from thirty to sixty minutes, 

 washed in water, run up into 70 per cent alcohol, and the excess of 

 sublimate removed with iodin. 



The eggs, bound up in masses when taken from the water}" killing- 

 fluids, were sometimes put into a 10 per cent solution of hypochlorite 

 of sodium or potassium to soften the connective tissue and the trans- 

 parent egg membranes. Over-exposure to these fluids was very hurtful 

 to the blastoderms, and generally the eggs were run up into TO per 

 cent alcohol and the shells removed with needles. 



The younger blastoderms were picked ott' the j^olks and sectioned, 

 but the protoplasmic processes from the periblast made it impracticable 

 to get the blastoderms in late stages away Avhole. These eggs were 

 cut whole, and for this purpose those killed in Perenyi's fluid, on 

 account of their soft yolks, were especially good. The j^olks of eggs 

 killed in formalin, if kept in alcohol long, tend to become hard, hence 

 they should be gotten into paraffin as quickly as possible. 



In order to orient whole eggs in the paraffin it is necessary to stain 

 them. By putting them in full strength borax-carmine for from one 

 to two minutes, the embryonic tissues take the stain before the yolks, 

 and there result red blastoderms on yellow 3^olks. 



The eggs were embedded in paraffin, and sections cut from 5 to 10 

 microns thick and stained either in Mayer's hjemalum or Heidenhain's 

 iron hematoxylin. The former gave such beautiful preparations and 

 was so easy to manage that it was almost exclusively used. 



HABITAT. 



Pipefishes are found in all the warm and temperate oceans of the 

 world, but are not exclusively marine. Day (1865) reports that Syng- 

 nathus aryyi'ost ictus ascends rivers in ('ochin China miles above tide 



