coe: nemerteans of west and northwest coasts. 31 



small reddish or yellowish bodies of irregular shape and without 

 nuclei also occur. Each corpuscle has a small oval or sjiheroidal 

 nucleus, eccentrically placed. The stroma of the cell is usually 

 colorless or very pale greenish, and in some cases encloses fine 

 globules of a reddish or yellowish color. 



Burger ('91, p. 484) found in these cells a distinct attraction sphere 

 with one or two centrioles, and his observations have been confirmed 

 by Bohmig ( '98) . 



The corpuscles often collect in rather large balls which float to 

 and fi-o vnth the movements of the proboscis sheath. In some forms 

 the corpu.scle8 are so numerous as to give the appearance of a com- 

 pact tissue in the microscopic preparations. Some of the smaller cor- 

 puscles resemble the cells lining the pi'oboscis sheath in the vicinity 

 of the dorsal blood vessel, and fi'om these cells they are thought to 

 originate. The fluid itself is usually colorless, although in Parane- 

 jiERTEs it has a pale reddish color. The corpuscles themselves are 

 colorless in most species, but occasionally, as in Amphiporus fla- 

 vescens, are tinged with yellow or red. 



Proboscis. 



The proboscis in a large proportion of the nemerteans is j^i'ovided 

 with one or more very highly specialized stylets usually constituting 

 a formidable armature. Such an armature occurs in all members of 

 the Hoplonemertea except Pelagonemeutes. This order thus 

 practically corresponds \\ath Max Schultze's order Enopla. The 

 members of the other oi'ders are destitute of such an armature and 

 constitute the order Anopla. 



In all forms the highly developed muscular walls are lined exter- 

 nally Tvdth a thin endothelium, loathed in the fluid of the rhynchocoel, 

 and internally by a very thick glandular epithelium. 



A. Paleonemertea and Heteronemertea. — Most of the Pale- 

 onemertea are characterized by a comparatively short proboscis and 

 proboscis sheath, but this })eculiarity is shared also by Taeniosoma. 

 JNfost of the Lineidae, on the other hand, have the proboscis at least 

 as long as the body, and in some forms it is twice as long, being 

 coiled up in the anterior portions of the rhynchocoel. 



Broad and thick species of Cerebratulus have a correspondingly 

 thick proboscis, while in slender forms of Lineus this organ is very 

 long and delicate. 



