NO. 5 HARTMAN : POLYCHAETOUS ANNELIDS 487 



among the orbiniids. Here the species of Theostoma Eisig- have a muscu- 

 lar, primitively derived proboscis whereas species of all other genera have 

 an epithelial, secondarily derived, spacious proboscis. 



The peristomium is provided with 2 pairs of short or long tentacular 

 cirri (pi. 61, fig. 1) ( Pilar gis, Ancistrosyllis and Cabira) or it may lack 

 appendages (pi. 63, fig. 1) (Loandalia and Talehsapia). There are no 

 parapodia, setae or acicula in the first segment. The peristomium may be 

 more or less sharply set off from the prostomium or the separation may be 

 less distinct, marked only by a shallow, transverse groove. 



The second, or first setigerous, segment is provided with dorsal and 

 ventral cirri ( Pilar ff is and Ancistrosyllis) or is without either dorsal or 

 ventral cirri (Loandalia and Talehsapia). Its parapodia may be uni- 

 ramous (Loandalia) or sub-biramous to biramous (Ancistroyllis and 

 Pilargis) in which the notopodium is represented by an acicular lobe. 

 True biramous parapodia may be present from the second, or not until 

 the seventh (some species of Loandalia) setigerous segment. In typical 

 parapodia the notopodium (except for its dorsal cirrus) is small, greatly 

 exceeded in size by the neuropodium. The former is provided with only 

 one or a few acicula (pi. 60, fig. 5) (Pilargis) or also heavy acicular 

 spines (pi. 61, fig. 4) which may be straight or curved (pi. 61, fig. 6) 

 (Ancistrosyllis) or it may have only weakly developed, fine capillary 

 setae (pi. 63, fig. 3) (Loandalia and Talehsapia). Acicula and setae are 

 located above the dorsal cirrus. Neuropodia are provided with one or a 

 few acicula and simple setae in whorled (pi. 61, fig. 5) (Ancistrosyllis 

 and Pilargis) or transverse series (Loandalia and Talehsapia) or there 

 may be also furcate setae (pi. 62, fig. 6) (some species of Ancistrosyllis 

 and Pilargis) . 



Neurosetae are all simple. They are distally pointed (pi. 61, fig. 8) 

 (Loandalia, Talehsapia and Ancistrosyllis) or distally falcate with bifur- 

 cated tip (pi. 59, fig. 4) (Pilargis). These may be accompanied with 

 furcate setae (pi. 62, fig. 3) ; the occurrence of the latter has been 

 recorded for some species of Pilargis j Ancistrosyllis, Talehsapia and 

 questionably Loandalia. The cutting edge of the main neurosetae con- 

 sists of a single row of teeth (pi. 60, fig. 3) (Ancistrosyllis and Pilargis) 

 or there may be many transverse rows of teeth (pi. 63, fig. 6) (Loandalia 

 and Talehsapia). 



The posterior end terminates in a simple, more or less papillated or 

 smooth ring in which the anal aperture is terminal (pi. 59, fig. 3) or 



2 Theostoma Eisig (1914) is preceded by Protoaricia Czerniawsky (1881) 

 which has priority. 



\ 



