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bulletin: museum of comparative zoology. 



In many other species, although the cephalic glands may be less 

 voluminous in front of the brain, yet they extend far back into the 

 esophageal region. In certain species of Carinella ( G. rubra. Text- 

 fig. 2) these glands occupy a thick layer about the cephalic blood 

 lacunae as far back as the brain region, while a layer of similarly 

 deeply staining glands closely surrounds the rhynchodaeum. In 

 other species {C.frenata) they occur only immediately about the 

 rhynchodaeum. In still other forms of the same genus ( C. albo- 

 cincta) an intermediate condition may exist, for those glands situ- 



FiG. 2. — Carinella rubra. Transverse section through head in front of brain 

 showing enormously developed cephalic glands both above and below cephalic 

 blood lacunae {hi), and around rhynchodaeum (r/i); tiv, cexihalic nerves. ^ 



ated in the wall of the rhynchodaeum may discharge their secretions 

 directly into the cavity of the rhynchodaeum, and are not usually 

 termed cephalic glands, although they are perfectly similar in char- 

 acter and doubtless have the same origin as the latter. The true 

 cephalic glands in nearly all instances open by a single, or occasion- 

 ally by numerous ducts ending on the tip of the snout immediately 

 over the proboscis pore. 



In the Heteronemertea they are particularly well developed in 

 Taeniosoma, where they occupy a great part of the tissues of the 

 head in the brain region, and stretch backward above this organ for 

 some distance into the esophageal region. They are commonly 

 much more closely massed in the dorsal than in the ventral portion 



' For references not mentioned under the text figures see the Explanation of Plates. 



