1901.] NATITRAI. SCIENCES OF PHILADELPHIA. 659 



of ammonia and followed by eosin in concentrated aqueous solu- 

 tion, three to five minutes. This is the stain that has been most used, 

 and is a very satisfactory one. The longer time in hoematoxylin 

 is best for nerve fibrous tissue and epithelial structures. The 

 Biondi-Ehrlich mixture, three hours, has been employed, but is 

 not very satisfactory except for connective tissue. The iron- 

 hrematoxyliu method together with Bordeaux red is an excellent 

 stain after a Flemming fixation, and the Hermann triple stain — 

 saffronin twenty-four hours, gentian violet six minutes, iodine 

 three hours — has also been used. 



Habitat. — Zygeupolla was found at Wood's Hole, in a sandy 

 beach of limited extent, bordering on a little arm of Buzzard's Bay 

 that is sepax-ated from the main bay by the point of land known 

 as Penzance. Here, just in the angle made by the bay shore and 

 Penzance, the sand has drifted in, replacing the usual stony or peb- 

 bly beach; and in this small area, which is uncovered at low tide, 

 are found, together with many other marine worms, especially 

 Annelids, several genera and species of Nemerteans. Both Gere- 

 hratulm leidyi Verr. and C. ladem Verr. occur there, but the 

 latter not abundantly; Mlcrura cceca Verr., Cephalothrix linearis 

 Oers. and Carinoma tremaphoros Thomp. With such a rich supply 

 of material in a spot very convenient to the INIarine Biological 

 Laboratory, it seemed unprofitable at that time to work over any 

 other localities, so I am unable to say anything in regard to the 

 distribution of Zygeupolia. Dr. Coe found this genus last sum- 

 mer in Quisset Harbor, about two miles farther north on Buzzard's 

 Bay, in a very similar habitat. 



When the sand, either above or below the low-water mark, is 

 turned over, Zygeupolia may be found, usually about a foot below 

 the surface. The turning up of the sand frequently breaks the 

 worm, but a number of })erfect specimens have been preserved. 



The Living Worm. — In life the worms vary considerably in 

 length, chiefly owing to different states of contraction, so that it is 

 difficult to say accurately what the true length is. The same worm 

 seems to have two normal states, beside that of actual contraction. 

 The first is that of comparative rest, seen in PI. XL, figs. 5, 

 6, which are sketches from living worms. In this condition, as 

 when lying undisturbed in a dish of water, the average length is 

 from 6-8 cm. . But Avhen in motion, crawling along the sides of 

 the dish, the worm becomes greatly extended, so that the indi- 



