478 The American Naturalist. [May, 
This new form is clearly a species undescribed, distinguishable at 
once from the others by the lack of dorsal sete on all but the anterior 
segments of the body. The ventral setz, on the other hand, are very 
large and stout, with strongly hooked tips,—diminishing in size near 
the two ends of the body. 
The following description will serve to identify the species. 
Phreoryctus emissarius, n. s. 
A very long and slender worm, six to eight inches, or more, in 
length (in alcohol), by .6 to .7 mm. in diameter,—the segmentation 
very distinct, the color pale red, the cuticle highly iridescent. The 
cephalic lobe is separated from the first segment by a rather deep 
lateral constriction. It is broadly rounded in front, and about two- 
thirds as wide as long. I do not see the transverse division of this 
lobe remarked by Vejdovsky and Beddard in the other species. Seg- 
ments nearly quadrate, four hundred or more in number. (An im- 
perfect specimen contained three hundred and seventy-five.) Sete 
single, acute, the first segment with two very small ventral and no . 
orsal ones. Four rows on the following segments to the eightieth or 
ninetieth; on the remainder of the body only two rows, the dorsal 
setæ disappearing. The last of this series become very minute and 
variable, and are frequently wanting on here and there a segment pre- 
ceding the last that bears them. The ventral sete are very large and 
long, and strongly hooked, but diminish in size at the two ends of the 
body. They project into the ccelom, when retracted, a distance equal 
to two-thirds the whole diameter of the worm. 
Two longitudinal blood vessels, both closely applied to the alimen- 
tary canal, one dorsal and one ventral, the dorsal one contractile. A 
pair of long contorted vascular arches in each segment, extending 
loop-like into the ventral ccelom, below the sub-intestinal vessel. 
Nephridia, a pair to each segment, opening upon the surface a short 
distance čz front of the ventral setz. 
Champaign, IIl., April 14, 1890. S. A. FORBES. ~ 
Sea-Urchin Excavations at Guaymas, Mexico.—Since the 
publication of my paper [NaTurauist, Jan., 1890] on sea-urchin ex- 
cavations, I have received a letter from Prof. F. W. Cragin, of Wash- 
burn College, Topeka, Kansas, from which I make the following 
quotations : 
“Du a short stay at Guaymas, Mexico, in the winter of 1882- 
8, I collected for Washburn College a considerable number of sea- 
urchins of two species, of which you afterwards sent me the names 
