coe: nemerteans of west and northwest coasts. 233 



movements of both organs are interdependent, so that when stylet 

 is everted to pierce the tissues of the host, the stomach is opened 

 widely to suck up the exuding fluids. 



Reproductive organs. — Sexually mature in September. Genital 

 pouches extend much farther forward than in almost any other 

 nemertean, reaching very nearly to brain (Text-fig. 44). Ovaries 

 regularly paired, with a single large pouch containing usually from 

 ten to thirty ova between each pair of intestinal lobes (Text-fig. 27). 

 Spermaries far more numerous, surrounding intestinal canal on all 

 sides ; as many as fifteen or more being sometimes found in a single 

 transverse section (Text fig. 28). As in most parasitic animals the 

 abundance of sexual products is greatly in excess of that in related 

 non-parasitic forms. 



Habitat. — This species lives when sexually mature among the egg 

 masses of Epialtus productus, the common kelp crab of the Cali- 

 fornia coast. Upward of one hundred of these little worms were 

 found among the eggs of a single crab at Monterey, California, in 

 1901. I was unable to determine whether the worms pass their 

 early life on the gills of the crab, as does C. carcinophila of the 

 Atlantic coast and Europe, but suspect that this may be the case. 



Amphiporus Ehrenberg, 

 Symbolae Physicae, Berlin, 1831. 



This is by far the most common genus on the Pacific coast of 

 North America and to it belong 21 of the 86 species of nemerteans 

 enumerated in this paper. 



The genus Amphiporus includes mostly I'ather stout, solid, often 

 flattened forms, usually of considerable size, which are capable of 

 an almost incredible amount of extension and contraction. A few 

 forms, however, are long and cylindrical, even when contracted, but 

 others can contract until the body becomes almost barrel-shaped. 

 The worms can neither swim nor roll up spirally. 



Proboscis provided with a single, well developed central stylet, 

 with a barrel- shaj)ed or conical basis, and with two or more 

 pouches of accessory stylets. Proboscis sheath usually reaches 

 nearly or quite to posterior end of body ; Avithout lateral diver- 

 ticula. Number of proboscis nerves ranges from 6 to more than 



