AUTHORS’ ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, JULY 26 
THE PELAGIC NEMERTEAN NECTONEMERTES 
WESLEY R. COE anp STANLEY C. BALL 
Osborn Zoological Laboratory, Yale University 
FIVE PLATES (SEVENTEEN FIGURES) 
More than twenty-five years ago Verrill (92) described a 
species of nemertean which differed from all other known flatworms 
in the possession of a pair of long muscular appendages, cirri, or 
tentacles, attached to the sides of the body immediately back of 
the head (fig. 1). This was made the type of a new family, Nec- 
tonemertidae, and was named Nectonemertes mirabilis. Since 
the publication of Verrill’s original description of the type species 
a number of other species and genera of closely related pelagic 
nemerteans from the deep oceans in widely separated parts of the 
world have been collected. Opportunity has now been afforded 
us for a detailed anatomical study of the specimens described 
externally by Verrill, whereby it is possible to supplement his 
descriptions by a more complete account of the internal structures 
and so add somewhat to the available knowledge of nemertean 
organization and relationships. 
Verrill’s description and figure indicate a type of structure well 
adapted to pelagic life. The specimens were collected in the 
North Atlantic Ocean in regions where the water was from 600 
to 1700 fathoms in depth. Verrill also describes (’92) two other 
specimens from about the same region which closely resembled 
Nectonemertes in form, size, general appearance, and structure, 
but which were without the lateral appendages. These he made 
the type of a new genus and species, Hyalonemertes atlantica, 
but, as will be explained below, it now seems evident that they 
represent the females of the sexually dimorphic Nectonemertes 
mirabilis. 
Besides the five specimens studied by Verrill, one additional 
excellently preserved specimen, which was collected by the U. 3. 
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