224 AMBLYOSYLLIS. 



gradually tapering and terminating in two short and slightly clavate caudal cirri. The 

 great pear-shaped egg-sacs are arranged alternately, so as to give room for the distal 

 globular region of each, and appear to occupy about ten segments. The dorsal cirri 

 are longest in the ovigerous region, and diminish to short processes posteriorly. The 

 alimentary canal is rudimentary, but is open in front. 



The relationships of this form have not yet been ascertained, though it is clearly a 

 female bud of an Autolytus having this characteristic method of carrying the com- 

 paratively large circular granular ova. Whether it has any connection with such forms 

 as Procer&a, Bhlers, which is here included under Autolytus, remains to be seen. 



Professor Graham Kerr 1 noticed that this form quite differed from the ordinary 

 female bud of Autolytus prolifer. 



The structure of the head, the arrangement and nature of the ovisacs, and other 

 features, distinguish it at once from Kolliker's three forms, viz., Exogone (Erstedii, 

 Exogone cirrata, and Gystonereis Edwardsii, 2 all of which bear ova in sacs. 



Genus LVI. — Amblyosyllis, Grube, 1857. 



Head short. Eyes, four pairs on each side, confluent. Tentacles and cirri long and 

 slender. Palpi small, appearing as two bosses on the ventral surface. Two nuchal flaps. 



Pharynx long, sinuous, armed with a point (trepan, Malaquin) and a circle of 

 papillge. Pharyngeal glands posteriorly, ventricule small, and with two minute cseca. 



Body of few segments; cirri thread-like, not articulated (Langerhans). Ventral 

 cirrus lanceolate. Falcate bristles bidentate. Penultimate segment provided with two 

 pairs of cirri (Malaquin). 



Grube's genus Amblyosyllis (18*57) has priority. 



Claparede 3 again established the genus Pterosyllis for this species, but the characters 

 had probably been known previously in this country. He describes the proboscis as 

 furnished with bifid cuticular papillse in P. formosa, which seems to be very closely allied 

 to P. spectabilis. His Pterosyllis dorslgera 4 may have some connection with a female of 

 the same species, though the moniliform condition of the cirri is noteworthy. Subse- 

 quently Ach. Costa, 5 without having seen Claparede's accounts, described probably the 

 same form under the name of Nicotia lineolata. The publication of the ' Catalogue of the 

 British Museum' 6 added another generic name for the same type, viz. Gattiola. 



Malaquin notes that the nuchal flaps (ailerons occipitaux) receive two large nerves 

 from the occipital lobes of the cephalic ganglia. Lang considers them organs of smell, 

 but Malaquin doubts this interpretation. 



i 'Trans. Nat. Hist. Soc. Glasgow/ N.S., vol. viii, p. 4 (1905-6). 

 3 ' Nouv. Mem. de la Soc. Helvetiqne/ Bd. vii, p. 14, Taf. iii. 



3 'Beobach u. Anat./ etc., p. 46 (1863), and ' Gdannres/ p. 100 (1864). 



4 ' Gdannres/ p. 100, pi. vi, fig. 1. 



5 < Ann. del Mns./ p. 160, 1864. 



6 'Cat. Brit. Mns./ p. 195. 



