1!)07.] NATURAL SCIEN'CES OF PIIILADKLPHIA. 203 



neuropodia and notopodia consist of \ertical ridges, each bearing a 

 series of lS-20 crochets and ending in minute notopodial and neuro- 

 ])odial cirri, while from their contiguous ends arise foliaceous expan- 

 sions borne on short stems (figs. 27-29). These expansions increase 

 somewhat in size to the middle of the body and bending toward each 

 other overlap broadly, but farther back they become much reduced in 

 size and the cirri disappear, simultaneously with an increase in the 

 number of crochets. 



Setse of both rami of the first nine pairs of parapodia (II-X) all 

 capillary, colorless, moderately slender, not greatly elongated, with 

 curved and tapered stems very delicately bordered by margins 

 which are broad on the concave and narrow on the convex side; 

 arranged in one regularly spaced series of from 15 to 30 and spreading 

 in a broad fan-shaped figure. Except that they are slightly longer, the 

 notopodials differ in no noticeable respect from the neuropodials, and 

 except that they are rather longer, more numerous and in part arranged 

 in double series, those of the tenth somite are exactly like the preceding 

 ones. Posterior to somite X both rami bear hooded crochets only, in 

 simple series facing each other; anteriorly each series contains 15 to 20, 

 posteriorly as many as 30. They (fig. 30) are little exposed, colorless, 

 slightly tapered distally, w^here they terminate in an abruptly hooked 

 blunt beak, surmounted by a smaller tooth and enclosed in a pair of 

 wide guards. 



Color translucent white, the intestine varying from buff to greenish- 

 brown, pharynx salmon pink, both showing through body walls; blood 

 madder pinlv, especially conspicuous in the tentacular cirri which con- 

 tain a large vascular loop. 



Specimens taken during the latter part of August contain nearly ripe 

 eggs in the middle segments of the body. 



Type No. 1677, Coll. Academy of Natural Sciences of Philadelphia. 



Lives in sand at and below low w^ater, forming soft sand tubes under 

 stones, etc. As the worm crawls the pharynx is everted as a tumid fold 

 or bulb reaching half the length of the head, the ventral median part 

 being most prominent and marked by delicate longitudinal furrows. 



This species has been found only on a sandy beach, chiefl}^ below^ 

 low water, in a little shallow bay on the Buzzard's Bay side of Wood's 

 Hole. Prof. E. A. Andrews found it at the same place about ten years 

 before it came to my notice, and has described a specimen under the 

 name of M. papillicornis Miiller. The remarkable larvae have been 

 described by Fewkes (as Prionospio tenuis) from Newport, and by 

 Andrews from Beaufort, N. C, and Wood's Hole. 



