234 bulletin: museum of comparative zoology. 



30 in different forms, but shows very little variation in the same 

 species. Ocelli are nsually present in very considerable nixrabers. 

 A few forms are without eyes, and a feAv others have but a single 

 pair — there are never four. The eyes do not extend far behind the 

 brain. Cerebral sense organs are usually well developed. Their 

 position is most commonly in front of the brain, but they are some- 

 times beside or even behind the ganglia. Neurochord cells absent. 

 Submuscular glands often well developed ; cephalic glands com- 

 monly much reduced. 



The genus Amphiporus may be looked upon as the genus most 

 characteristic of this region, including as it does nearly one fourth 

 of the total number of species known at present from this localit3^ 

 Upwards of 50 species of this genus have been described from other 

 parts of the world, of which only 1 {A. cruentatus and A. angula- 

 tus) are as yet known from the Pacific coast. 



An even larger proportion of the nemerteans of the Atlantic 

 coast of North America belong to this same genus, however, for 

 here 18 out of a total of 62 species have been referred to the genus 

 Amphiporus, and on the northern coasts of Europe an abundance 

 of species of this genus is encountered. As a rule, the species are 

 of considerable size, and great numbers of individuals often occur 

 in the same locality. In the cooler waters of the Southern Hemi- 

 sphere also a considerable })roportion of the nemerteans thus far 

 described belong to this genus. 



In the tropics, however, as remarked by Punnett (:01, p. 101), 

 very few species of Amphiporus occur, so that a characteristic 

 feature of collections from the Indian Ocean, Polynesia, and other 

 tropical localities, is the great scarcity of representatives of this 

 genus. 



An examination of the anatomical peculiarities of the 21 species 

 represented in the region covered by this report reveal certain inter- 

 esting deviations from the average type from other quarters of the 

 globe. Some of the more important of these characters, and 

 especially those relied upon in classification, are here presented in 

 tabular form in order that a comparison of all the species repre- 

 sented in regard to these particular characters may be facilitated. 

 In the last column a single deviating character is mentioned for 

 some of the species. 



