>To. 104.] 155 



stride, interrupted by transverse strias, uneqnallj distant from each 

 other; at the fourth setigerous segment the number of uncini in- 

 creases suddenly to ten or fifteen in each series, and the form also 

 changes (tig. 59) ; they have now five terminal teeth, a short, ex- 

 ternal part is quite narrow, and divided from the stouter, internal 

 part by a deep constriction, simulating a compound seta ; the thirty- 

 seventh segment has only the dorsal setie ; to the tenth segment the 

 setfe are found in the middle of each segment ; after the tenth they 

 suddenly recede to near the posterior end. 



Three specimens were collected — one perfect, the others with 

 anterior part only; and of these only one, having the ten anterior 

 segments, was observed while living ; its general color was yellowish- 

 white, with narrow, red bands on the posterior part of each seg- 

 ment after the fourth, increasing gradually in width so as to occupy 

 one-half the length of the tenth segment; indications of similar 

 bands can be traced on the entire specimen, in alcohol, but not after 

 the tenth segment. 



Length of entire specimen, 95™°^; greatest diameter, S™'"; diam- 

 eter of buccal segment, 2™". 



ISTuraber of segments, 39 ; buccal (coalesced with the cephalic), 

 1 ; setigerous, 36; ante-anal, nude, 1; anal, 1. 



Rare ; found in sand at low water, associated with Clymenella 

 torquata Verkill. 



Praxtlla elongata var. Benedicti Webs. 



PLATE (Yl), IX, FIGS. 60, Gl. 



Mr. J. E. Benedict found at South Norwalk, Conn., a variety of 

 this species, differing from the form just described in the following 

 particulars : 



First two segments short (fig. 60), together about equal to the 

 third; after the fifteenth segment the diameter suddenly becomes 

 less, segments short, and, except the last four, equal. (Compare 

 the first segment of fig. 61 with the first of fig. 56.) The ante-anal 

 segments (fig 61), quite short, together equal to the anal ; anal cirri 

 longer than in the New Jersey form. 



Length of an entire specimen, 20™™; number of segments, 37. 



A young specimen had twenty-six segments, with a length of 3™™. 



PARAXIOTHEA n. gen. 



No cephalic plate. 



Anterior margin of first segment prolonged as a thin membrane, 

 emarginate above, and with a slightly projecting conical process in 

 the middle line below. 



Mouth situated on the lower surface of a conical process, arising 

 from the bottom of the cylindrical cavity inclosed by the frontal 

 membrane, not reaching to the front margin of the membrane. 

 First segment with capillary and uncinate setne, similar to those on 

 the remaininof sesrments. 



Anal segment funnel-shaped; margin digitate. 



