1905.] NATURAL SCIENCES OF PHILADELPHIA. 557 



Besides the peristomiiim there are S setigerous thoracic somites,"alI 

 uniannulate and separated by deep segmental furrows. The region is 

 nearly cylindrical, but slightly depressed and from 3 to 3.5 mm. wide. 

 The 8 ventral glandular plates, including the first, are all transversely 

 oblong and the second and third only are divided transversely into 2 

 equal halves. Abdominal somites are also uniannulate and the pos- 

 terior ones much crowded. Thick ventral plates are developed 

 throughout the region and are divided into halves by a deep faecal 

 groove extending from the anus to the first abdominal segment, cutting 

 the latter oblic^uely to the right and entering the thoracico-abdominal 

 fm-row in front of the setae, then appearing again faintly in the dorsal 

 mid-line of the thorax and entering the dorsal fissure. 



Thoracic parapodia are strictly lateral and the uncinigerous tori 

 flush with the surface, while the setigerous tubercles may project 

 slightly or be retracted within little pockets. The collar setse form a 

 very small tuft and the remaining 7 fascicles are somewhat elongated 

 laterally and oblique. On all thoracic somites the uncinigerous tori 

 are separated ventrally by about ^ and dorsally by nearly or quite h the 

 body circumference. They increase in length gradually to the third 

 which equals the ventral interspace, then decrease to the last which 

 is f of the longest, while the first equals the fifth or sixth. As the tori 

 shorten the setae tufts, closely approximated to their dorsal ends, 

 assume a correspondingly lower position. Abdominal parapodia are 

 more prominent and distinct lateral elevations, highest at the position 

 of the setsD tufts near their ventral ends. The anterior tori are, like 

 the thoracic ones, nearly flush with the surface and are consequently 

 transitional, but, like all of the others, they are separated from the 

 ventral plates by a deep longitudinal groove. Both setae and uncini 

 are in strictly vertical, linear series. On the first abdominal segment 

 the former has a length of about + that of the setaD tuft, and the latter 

 equals the uncinigerous torus of the last thoracic somite. From this 

 point both gradually diminish in length and number of setae or uncini 

 to the caudal end. At the dorsal end of each thoracic and the ventral 

 end of each abdominal torus is a small, eye-like pigment spot. 



In the collar tuft all setae are capillary, winged, lanceolate, the ven- 

 tral ones, however, shorter and with wider wings than the dorsal. On 

 the remaining thoracic somites the setay are of two sorts; a few in the 

 dorsal and anterior part of the fascicle resemble the collar setae (fig. 

 1), the number of which decreases from anterior segments backward. 

 Those in the ventral and posterior portions of the bundle form a com- 

 pact phalanx of several rows of obovate paddle-shaped or spatulate 



