"VIII. — On the Anatomy of a species op Nemeetean ( Cere- 

 bratulus lacteus Verrill), with remarks on certain other 

 SPECIES. By Wesley R. Coe. 



This species of Neraertean is found in abundance on the southern 

 coast of New England burrowing in the hard sand or sandy mud 

 near low-water mark, and at some distance both above and below. 

 Living in the burrows with these worms there is often found a 

 species of Planarian (Eustylochus ellipticus) which apparently 

 feeds upon the sticky mucus which lines the burrows and is 

 secreted by the integument of the worm. This species of Nemertean 

 has a wide range of distribution, being found along the Atlantic 

 coast from Maine to Florida. It is a particularly active species and has 

 the posterior portion of the body broad and flat, so that it is well 

 adapted for swimming. It is often met with at night swimming 

 near the surface of the water with motions like those of an eel. 

 These worms live well in captivity during the cooler portions of 

 the year in a very limited quantity of sea-water, but although I 

 have kept the sexually mature animals long past the normal time for 

 the deposition of the genital products, these were not discharged 

 and the worms finally died. Fragments without heads remain alive 

 for several weeks. 



The external anatomy of this species has been so admirably 

 described by Verrill (1)* that it is intended in this paper to treat 

 of the internal anatomy and histology only. For the most part, 

 serial sections in parafiin have been used, although for histological 

 study the tissues are readily macerated in a dilute solution of 

 formalin, as described below. 



For the preservation of Nemertean s for histological study, good 

 results are obtained by the use of hot, not hoillng^ fluids. A satu- 

 rated solution of corrosive sublimate, a two per cent, solution of 

 chromic acid, or water to which a little formalin has been added, 

 may be employed. If chromic acid be used the worms should remain 

 in the fluid for 24 hours and then be washed for several hours in run- 



* The number in brackets after an author's name refers to the number of the paper 

 In the bibhography at the end of this article. 



