4 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
In 1900 the last quarter of the moon occurs on June 19 and July 18; 
and as we do not yet know the limits of the lunar month in which the 
worm swarms, we may look for it within three days of either of the 
above dates along any of the Bahama or Florida reefs. It seems not 
improbable that it swarms annually on one day of the year, and that 
this day falls within three days of the moon’s last quarter in the month 
extending from June 15 to July 15. 
Description of the Adult Worm. —The genus Staurocephalus was 
founded by Grube, 1855, who has given a synopsis of the genus and a 
description of all of the then known species in the Jahres-Bericht der 
Schles. Gesell. fiir vaterl. Cultur., Bd. 56, pp. 109-115, 1878. Since 
then two new species have been described by McIntosh (85, pp. 231- 
235) ; and references to previously described species have been given 
by Ehlers, Verrill, and Andrews. 
Generic Characters. — Annelida, Polycheta, Family Nereide ; body 
vermiform, segments distinct. The head-lobes give rise to one or two 
pairs of jointed tentacles. When two pairs of tentacles are present, one 
pair arises from the side, and the other from the ventral surface. Eyes 
are sometimes present. The two first segments are without parapodia. 
The parapodia possess dorsal and ventral cirri. The dorsal cirrus is 
often unjointed, but sometimes possesses a short terminal segment. 
The ventral cirrus is shorter than the dorsal and is unsegmented. The 
posterior segment has two long dorsal and two short ventral cirri. 
The upper jaw consists of two simple, connected pieces. . The lower 
Jaw consists of two rod-like pieces which approach each other near the 
middle but diverge both in front and behind. (See Figures 20, 22, 26, 
27, Plate 3.) 
Specific Characters ; Adult Worm. —The worm is about 120-150 mm. 
in length; and may be even longer, for the posterior segment has not 
been observed. The segments are distinct, and there are about 17 
roetameres per centimetre of the worm’s length. The worm is about 
4mm. broad. The ventral surface is quite flat and a deep groove runs 
down its centre. The dorsal surface is arched, and the dorso-ventral 
diameter is about 3mm. There are no eyes, but the hypodermis cells 
of the front end of the prestomium bear a dark rosin-colored pigment, 
the presence of which may indicate a general sensibility to light. There 
are no lateral tentacles upon the head, but the ventral prestomium 
gives rise to two quite stiff tentacular cirri (see Figures 1-3, 9-12). 
These cirri consist each of but a single joiut. An axial nerve runs 
down the centre of each tentacle, and this nerve is surrounded by 
