198 CHAETODERMA LUCIDUM. 



likewise glandular, and continue in this condition for a considerable distance 

 beyond the union of the pro- and metathorax (Plate 12, fig. 14) where the ali- 

 mentary canal attains a greater diameter (Plate 12, fig. 5). Sections were not 

 made of the mid region of the body. Posteriorly the intestine pursues the 

 usual course and opens in typical fashion into the cloacal chamber. 



The cloacal cavity, so far as shape and relations are concerned, is not 

 unusual, but its epithelial lining, especially near the posterior end of the ani- 

 mal, is highly glandular, the cells staining intensely in haematoxyhn. Gland 

 cells with similar staining reaction occur in the branchiae, and are limited 

 to very definite zones (Plate 12, fig. 13). A comparatively small number occur 

 in the external epithehal layer immediately dorsal to the dorsal branchial sinus, 

 and a much larger proportion is imbedded in the lamellae, forming in sections 

 a horizontal band passing through the dorsal limit of the ventral gill retractors. 



The circulatory system presents no unusual features. The sinus returning 

 the blood from the branchiae to the heart is unusually large and clearly defined 

 and the pericardial chamber (Plate 12, fig. 15) is more spacious than common, 

 but otherwise the heart, aorta, and sinuses are fashioned upon the usual plan. 



The coelomoducts open into the pericardial cavity beside the posterior 

 dorsal commissure by means of well-defined, ciliated mouths, and from this 

 point extend anteriorly, rapidly losing the ciliated coat and assuming the char- 

 acteristic vacuolated appearance, until they have traversed on half of the length 

 of the main or ventral portion of the organ with which they unite. This main 

 division presents no especially noteworthy peculiarities. The Uning epithelium 

 is composed of very clearly defined cells with basal nucleus, and in living material 

 the distal two thirds was evidently filled with some non-staining material that 

 in sections has escaped leaving only the ruptured cell membrane. The openings 

 into the cloaca (Plate 12, fig. 13) are normally placed and are not surrounded 

 by the high columnar cells encountered in several species of this genus. 



The nervous system, in its broader details at least, conforms closely to 

 the usual type, and therefore calls for no description beyond that afforded by 

 the figures. 



Chaetoderma lucidum, sp. nov. 



Fifteen specimens of this species, the majority of them mutilated, were 

 dredged approximately one hundred and forty miles to the eastward of Cape 

 May, New Jersey (Sta. 2588A) at a depth of 479 fathoms. Fully as many more 

 were taken on another occasion slightly to the northeast of this point (Sta. 2212A) 

 at a depth of 428 fathoms, but unfortunately all from this last named locaUty 



