84 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



I. Paleonemertea. This order will thus include the following 

 families and genera at present known from the Pacific coast : 



Family Carinellidae : Carinella, Carinomella. 

 Carinomidae : Carinoma. 

 Cephalothricidae : Cepiialothrix. 



II. IIeteroxemertea. In regard to the many genera which are 

 characterized by the possession of three musciilar layers, of which 

 the middle layer is circular and lies immediately internal to the 

 lateral nerves, the order Schizonemertea is so very inappropriate, as 

 stated above, that Burger's order Heteronemertea is ado}»ted with- 

 out hesitation in this article. The following families and genera of 

 this order ai'e known to occur on the Pacific coast : 



Family Taeniosomidae : Taeniosoma. 



Lineidae : Euborlasia, Lineus, Zygeupolia, Micrura, 

 Cerebratulus. 



III. Hoplonemertea. As Burger's order Metanemertea is equiv- 

 alent to Hubrecht's older order Hoplonemertea there seems no 

 reasonable ground for discarding the older of the two names, so 

 that Hoplonemertea is adopted in this article, and includes the fol- 

 lowing families and genera from the Pacific coast : 



Family Emplectonemidae : Emplectonema, Nemertopsis, 



Paranemertes, Carchstonemertes. 

 Amphiporidae : Amphiporus, Zygojstemertes. 

 Tetrastemmidae : Tetrastemma (Oerstedia) . 

 Drepanophoridae : Drepanophorus. 

 Pelagonemertidae : Plaxktoxemertes. 



IV. Bdelloxemertea. The genus Malacordella differs so 

 widely from all other nemerteans that it clearly demands a distinct 

 order. For this order Verrill ('92, p. 444) proposed the name 

 Bdellomorpha, a name which might reasonably be retained. This 

 name, however, does not conform with those of the three other 

 orders, all of which have the suffix -nemertea, so that I would sug- 

 gest that the order be, for the sake of uniformity of nomenclature,, 

 designated by the new name of Bdellonemertea. 



The characters of this order are as follows : Pai'asitic nemerteans 

 with short, stout, flattened bodies of leech-like a})pearance and move- 

 ments, with sucker at posterior end of l>ody ; mouth and proboscis 

 have common opening at emarginate anterior end of body ; head 

 devoid of lateral grooves, cerebral sense organs and ocelli ; proboscis 



