310 THE ANNELIDA POLYCHAETA. 



the expanded portion bearing the masticatory plate slender, nearly uniform in 

 width anteriorly, the caudal ends of the two bending mesad toward each other, 

 the mesal edge of each bulging mesad near middle of length; the two stems 

 firmly united just caudad of the masticatory plates. (Plate 39, fig. 5). 



Numerous tubes are represented in the collection. These are all con- 

 spicuously flattened, and are moderately narrowed toward one end. A typical 

 tube is about 40 mm. long and 5 mm. wide at the larger end, the lesser diameter 

 being but 2 mm., or scarcely more. There is the usual thin, but moderately tough, 

 lining membrane densely encrusted with the shells and shell-fragments of vari- 

 ous Foraminifera. Of these shells the large discs of Spirillina are especially 

 conspicuous, occur on all the tubes, and range in diameter from 4 mm. down. 

 In addition, shells of Globigerina are abundant, as are also those of Nodosaria. 

 The elongate shells are nearly always arranged either strictly transversely or 

 somewhat obliquely. 



Locality. Off Panama: Sta. 3392 (lat. 7° 05' 30" N., long. 79° 40' W.). 

 Depth 1,270 fms. Bottom temp. 36.4° F. Bottom hard. Numerous tubes 

 containing animals. 10 March, 1891. 



This form is characterized particularly by the large maxillae III with their 

 large number of teeth (ten to thirteen), exceeding the number on maxillae II 

 (eight to nine) , and the presence of pectinate setae in abundance as far forward 

 as the second parapodia, as well as by the detailed structure of the setae, form 

 of the cirri, and other details. The tube in being strongly flattened differs con- 

 spicuously from those of Paradiopatra fragosa and P. glutinatrix described by 

 Ehlers (Mem. M. C. Z., 1887, 15, p. 75, 76) from off Florida and made the basis 

 of Paradiopatra, the tubes in these two latter species being cylindrical. 



Hyalinoecia Malmgren. 



Annulata Polychaeta 1867, p. 67. 



Hyalinoecia tecton, sp. nov.^ 



Plate 38, fig. 4-9; Plate 39, fig. 1, 2. 



The general color of the specimens from Sta. 3424 is light yellow, in some 

 becoming darker in the caudal region. In the caudal region and for a vary- 

 ing distance forward there may be a conspicuous, geminate, discontinuous median 



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