NEMERTEANS 



ISS 



Central stylet slender and acutely pointed, having a very slender basis 

 of about the same length as stylet. 

 Basis peculiar in that it is no wider, 

 and is often narrower, posteriorly than 

 at attachment of stylet. It is often irreg- 

 ular in shape (p1. xx, figs. 1-5) and 

 about five or six times as long as its 

 average width. Measurements vary 

 from 0.07 to 0.1 mm. in length and 

 0.013 to 0.017 mm. in width. Two 

 pouches of accessory stylets contain 

 from two to four slender stylets each. 

 Proboscis sheath reaches very nearly to 

 posterior end of body. Retractor mus- 

 cle of proboscis composed of about six 

 strong fibers, attached in two groups 

 to wall of sheath. 



Blood system as in related spe- 

 cies. In every individual of a large 

 number of specimens the dorsal, or 

 proboscis sheath vessel originated ante- 

 riorly from the right lateral vessel (text 



fig- 19)- 



8. AMPHIPORUS PAULINUS Punnett » 

 Proc. Zool. Soc. London, p. 92, 1901. 



Punnett describes this new species from several specimens collected 

 by Professor D'Arcy Thompson in the Pribilof Islands. This is de- 

 scribed as being a slender form, 50-90 mm. in length and up to 4 mm. 

 in greatest diameter. Color in life unknown, but after preservation 

 the worms assume a pale yellowish brown color dorsally, and are 

 almost white ventrally. Submuscular glands well developed, reaching 

 back to intestinal region. Intestinal caeca do not reach nearly to the 

 brain. Proboscis sheath extends only about six sevenths the length of 

 the body ; the proboscis is about three fourths as long as body and 

 contains fifteen nerves. Its armature consists of central stylet and 

 two pouches with four reserve stylets each. Basis is same length as 

 central stylet. A single efferent nephridial duct lies on each side. 

 Cerebral sense organs small, situated immediately in front of brain. 

 There are numerous ocelli. 



* For the sake of completeness this species is included here, although it ha» 

 not been studied by the writer. 



._/ir 



Fig. 19. A. cruentatus. Dia- 

 gram of anterior portion of body, 

 showing ocelli ; br, brain ; cv, dv, 

 Iv, cephalic, dorsal and lateral 

 blood vessels. X 30« 



