1911.] NATURAL SCIENCES OF PHILADELPHIA. 293 



occur. Ehlers states that crochets occur on all podous segments, the 

 anterior being limbate and that acute limbate setae cease at LV. On 

 my material crochets may begin on the first foot (III), which is usual, 

 or they may be absent for from four to twelve anterior parapodia. This 

 is notably the case in three specimens from station 4,523, in which the 

 first occurs in X, XII and XIV, respectively, the first two specimens 

 being about 5 mm., the last 3 mm. in diameter. On two still larger 

 specimens 5 mm. and 7 mm. in diameter, from stations 4,406 and 4,402, 

 no crochets were detected anterior to XIX and XXI, respectively. 

 The passage from limbate to true crochets is a gradual one, but typical 

 crochets may usually be recognized at about the fortieth parapodium. 

 The last limbate seta may occur anywhere from segment XLII to 

 segment LXXXIX, the average of fourteen specimens on which this 

 was determined accurately being LXIV. There is no relation between 

 size and the position of the last acute seta, as there is in the case of the 

 first crochet. The variation, however, is less than would appear, for 

 in cases where a large number of parapodia contain acute, limbate 

 setae, the last twenty or thirty bear but one. 



Few of the specimens are obviously pigmented. Most are of a 

 dull gray or yellowish-brown color, one having a russet ground color is 

 marked with narrow dark brown annulations, and one lot from station 

 4,454, like other species from the same station, is marked with quad- 

 rate black spots. The ground is pale slate color with cuticular iri- 

 descence. The spots are sharply defined, always confined to one 

 segment, though those of adjacent segments may coalesce. They 

 occur on both dorsal and ventral surfaces, somewhat more plentifully 

 on the former, and apparently increase toward the middle region, 

 leaving the ends of the body less maculated. Individuals differ 

 greatly in the richness of the spotting, some having very few and 

 widely scattered spots, while on others they are numerous and often 

 confluent; some have the prostomium unspotted, while on others it 

 bears from one to three spots. 



In all seventy-seven specimens, ranging in diameter from .8 mm. to 

 7 mm., were examined, and although only a very few were complete 

 all exhibited the characteristic alteration in the form of the parapodia 

 from before caudad and the characteristic arrangement of the setae. 

 A complete specimen 155 mm. long has 312 segments, and at the point 

 of maximum diameter (XVII) the width is 3 mm. (exclusive of the 

 parapodia) and the depth 2.4 mm. A medium-sized specimen from 

 station 4,574 is packed with eggs. 



Although taken at many stations throughout the whole range of 



