292 ALLEN. [VOL. 1. 



two hours, washed again in running water and cleared for a 

 few seconds in iron-alum. After rinsing in distilled water 

 they were plunged into 95 per cent alcohol, carried up and 

 mounted in balsam. The best results were obtained by leav- 

 ing the slides in each stain for an hour. This method was 

 of greatest value in study of the segmentation of the egg. 

 The cytoplasm appeared gray, chromatin fibers black. 



In using the eosin-haematoxylin method the sections were 

 stained for an hour in a 2 per cent solution of eosin in 90 per 

 cent of alcohol, after which they were stained in a weak solu- 

 tion of Delafield's haematoxylin for twenty minutes. This 

 stain gave very good general differentiation, and was of espe- 

 cial value in determining the origin of the sex cells. 



A number of other stains and combinations of stains were 

 used with fair success. 



General Description of ParypJia. 



Parypha crocea is found all along the New England coast 

 attached to floating timbers and the piles of wharves. It 

 seems to prefer brackish water and partial sunlight, but often 

 occurs in pure sea water. 



This hydroid grows in colonies which arise from a single 

 individual by a process of budding, and the sexes are always 

 separate. The hydrorhiza is made up of a contorted mass of 

 irregularly branched stems, from which the hydrocaulus of the 

 individual hydroid arises. The stems bearing the adult polyps 

 are usually two and a half to three inches in length, and short 

 stems are sometimes found branching out from the main ones. 

 Enclosing the stem is a horny, often annulated sheath, the peri- 

 sarc. The polyp is borne at the top of a somewhat globular 

 expansion of the hydrocaulus, and is almost conical in form, 

 with a broad, saucer-shaped base. It contracts about three- 

 quarters of the way up, forming a thick-walled, flexible pro- 

 boscis, in the center of which lies the mouth, surrounded by a 

 circle of short, thick tentacles with decurrent bases. Around 

 the base of the polyp is a circle of long, slender tentacles, vary- 

 ing in number from sixteen to twenty-four. The medusoids 



