222 



rJtJLLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



tral and accessory stylets exhibit the same braided appearance, and 

 are of the same size and shape when mature. 



Variations in size of central stylet and its basis in several individ- 

 uals are given below : 



The specimen with the smallest stylet apparatus included above 



measured but 1 cm. in length, while several 

 with the lai-gest stylets were 15 to 20 cm. 

 long. As a general rule the larger indi- 

 viduals have the larger stylet and basis, 

 but the correlation in size is not very exact, 

 and is subject to many exceptions. The 

 basis averages a trifle shorter than the 

 stylet itself, and the largest stylet measured 

 is just twice the length of the smallest. 



All the Californian specimens examined, 

 whether from Monterey Bay or San Pedro, 

 differ therefore from most individuals col- 

 lected in Alaska in the number of lateral 

 stylet pouches as Avell as in the number of 

 accessory stylets. Four pouches are com- 

 monly found in Alaska specimens, but I 

 have not yet seen any individual from 

 California with more than two. In Alaska 

 there are commonly 6 to 10 accessory sty- 

 lets in each lateral pouch (Coe, : 01, p. 34), 

 while, as shown above, 2 to 4 is the rule in 

 California. The largest individual which T examined in California, 

 however, measured but 25 cm., while I have collected specimens in 



Fig. 38. — Paranemertes pere- 

 grina. Outlines of central 

 stylets and bases, showing 

 peculiar sjurally grooveil 

 appearance of stylet. 



