ANATOMY OF SUTROA ROSTRATA. 7 



o])(_'(l. In the iilbuminous gland, however, I have searched in vain for any, though 

 I must cont'css the number of specimens at my disposal has been very small. 



The seginental organs are found in all the segments posterior to XII. They 

 consist of long slender organs, the body of which is destitute of any glandular 

 appendices oi' cells similar to those found in Rhjiichelmls. The interior opening of 

 the organ is surrounded by brown glands, behind which there is a larger head-like 

 enlargement of similar structure to the duct proper (Fig. 12). 



The spines are eight in every segment and occur in four pairs. They are 

 slightly S-shaped, entire, not forked (Fig. 1.3). 



EXPLANATION OF THE FIGURES. 

 Plate I. 



Fig. 1. Sutroa rostrata, natural size. 



Fig. 2. Front part of the worm, with the cephalic lobe, showing its filiform 



elongation. 

 Fig. 3. Transverse section of the body of a quadrilateral specimen. 

 Fig. 4. The front part of the worm, showing the vascular or circulatory 

 system. The dorsal vessel is represented red ; the ventral 

 vessel, blue. 



d. pr. v.: dorsal perigastric vessel. 

 V. pr. V. : ventral perigastric vessel. 

 Fig. 5. The twelfth to fourteenth segments, showing the vascular system 

 in those segments. 



ac.: alimentary canal, 

 dv. : dorsal vessel, 

 d. pr. v.: dorsal perigastric vessel, 

 d. gr. v. : dorsal gastric vessel. 

 Fig. 6. The efferent ducts and atrium, 

 ps. : penis. 



eff. d.: efferent ducts, 

 atr. : atrium. 

 Fig. 7. Efferent fuiuu'l more magnified and seen in different aspect. 



