62 University of California PuMicatiotis in Zoology [Vol. 18 



GENERAL DESCRIPTION 



The Amphinomidae are interesting in many ways. They have 

 been a problem to the various workers as to their place in the poly- 

 chaeta group and the question has not been definitely settled yet. Some 

 authors as Quatrefage (1865), have separated this family from the 

 Aphroditidae by the Palmiridae, Leodocidae and Lumbrinereidae. 

 Others, as Mcintosh (1900), disapprove of this division, claiming that 

 anatomical differences are not sufficient to justify it. Further dis- 

 agreement prevails among the various workers as to the classification 

 of this group. Some, as Ehlers (1864), deal with the Amphinomidae 

 as one family. A number of other workers treat them as two inde- 

 pendent families, Amphinomidae and Euphrosinidae. Mcintosh in 

 his first work (1885) treats the Amphinomidae as two independent 

 families, but in his later volume (1900) he places the subfamilies 

 Amphinomina and Euphrosynina under the one family Amphino- 

 midae. I am inclined to follow the latter plan of classification. 

 Besides the various other characteristics common to both subfamilies 

 of the Amphinomidae, the presence of a dorsal caruncle and the loca- 

 tion of the mouth, which is removed ventrally from the usual posi- 

 tion at the tip of the snout, distinguish the Amphinomidae from all 

 other families of the Polychaeta. 



The chief characteristics pertaining to both subfamilies are as 

 follows: The body is oblong or ovate-oblong. The cephalic lobe is 

 rounded or compressed and coalesced with the caruncle. The caruncle 

 extends over several segments. Of the two pairs of eyes both pairs 

 may be situated dorsally, or one pair may be situated ventrally and 

 the other dorsally. In the family Amphinomidae, there are two lateral 

 tentacles and one median. The latter, however, may be absent. The 

 mouth is removed from the anterior end ventrally and is surrounded 

 by specially modified segments. The proboscis is protrusible, devoid 

 of papillae and of chitinous jaws. The parapodia are biramous and 

 peculiarly modified. The notopodium extends on the dorsum and is 

 coalesced with the latter. It bears setae, branchiae and cirri, arranged 

 in transverse rows, frequently covering the entire dorsum of the worm, 

 except a narrow mid-dorsal line. The setae are usually of two or more 

 kinds; they are tubular, calcareous, very brittle, simple, capillary, 

 unequally bifurcate or serrate. The branchiae are arborescent or 

 pinnate; dorsal in Euphrosynina, marginal in Amphinomina. The 

 ventral cirri are single, the dorsal, single or double. 



