



BY WILLIAM A. HASWELL, M.A„ B.SC. 655 



vessels the only remarkable point I have noticed is the great 

 development in the dorsal, opercular, and branchial trunks of 

 Vermilia of a relatively very thick layer of circularly arranged 

 muscle with a few elastic fibres. A similar coat has bean detected 

 in the principal vessels of several other Annelids, s. g. Phreoryetes. 

 The blood in most of- the species of Serpulidce which I have 

 examined is a light green colour. Under the action of alcohol it 

 coagulates to form a clear clot which stains very readily with 

 hematoxylin or carmine. Within the lumen of all the vessels, 

 but usually close to the periphery, are to be observed a 

 number of clear oval bodies (pi. XXXIV., fig. 5, a a., b.b.) 

 usually of 75 I xl th of an inch in diameter, though smaller 

 ones are to be observed here and there. These bodies never 

 become stained under the action of any staining fluid more 

 intensely than the coagulum of the blood by which they are 

 surrounded. They may be seen to lie free in the cavity of the 

 vessel in the living animal and to move with the motion of the 

 blood, but examination of a number of sections will show now 

 and again one of these bodies connected with the wall of the 

 vessel by a narrow neck which is continuous with the clear 

 substance of the body itself. Corpuscles have been already 

 detected in the pseudohemal system of several genera of 

 Annelides(l), and doubtless such of the bodies above described 

 as lie free in the cavity of the vessel are of this nature. The 

 occurrence, here and there, of corpuscles connected with the wall 

 of the vessel would seem to point to the derivation of the free 

 corpuscles from the endothelium. 



SEGMENTAL OEGANS AND " TUBIPAEOUS GLANDS." 



The pair of large and conspicuous glands found in the anterior 

 part of the bod} r in the members of this group, have been set 

 down by Claparede as the only equivalents of the " segmental 



(1) J. E. Blomfield ami A. G. Bourne, Q. J. Micr. Sci. XXI flSSl), pp., 

 500-501; Man, " Ueber Scoloplos armiger," Zeitschr fiir Wiss. Zool., 

 XXXVI., p. 3S9, Kolleston, "Blood Corpuscles of the Annelides," Jour. 

 Anat. Phys. XII., p. 401-419. 



