84 PROCEEDINGS OF THE ACADEMY OF [Feb., 



Key to the genera Ophioconis, Ophiochceta and Opkiolimna in wide sense. 



A — Arm spines long, flagellate, not appressed. 



a — Outermost oral papilla very large and operculiform ; peris- 

 tomal plates very short and wide, nearly entire, with fairly 

 soldered halves and without a third median secondary 



plate Ophiolinma, emencL 



aa — Outermost oral papilla pointed inwards, stretching above 



the next papilla, which is the largest; peristomal plates 



rather long and wide, distinctly triple, consisting of two 



paired and one median secondary plates. 



b — Oral shields entirely covered with granules; arm plates 



usually concentrically striated; vertebrae of distal 



arm joints often divided into halves; arm spines 



hyaline; one or two tentacle scales, neither of which 



overlaps base of lowest arm spine. 



c — Teeth triangular and pointed, not hyaline; ventral 



arm plates wider than long, usually separated from 



each other Ophiuroconis nov. 



cc — Teeth flat, thin, with widened and often serrate end, 

 hyaline; ventral arm plates longer than wide, dis- 

 tinctly in contact with each other Ophiurodon nov. 

 hh — Oral shields naked; arm plates not concentrically striated; 

 vertebrae always entire; arm spines opaque; two 

 tentacle scales, of which the abradial one overlaps 



base of lowest arm spine Ophiurochceta nov. 



AA — Arm spines very short, peg-like, lying flat on arm. 



d — Oral shields covered with granules; arm spines 



hyaline Ophioconis, restr. 



dd — Oral shields naked. 



e — Arm spines hyaline; disk covered with granules,. 



"Ophioconis" indica. 



ee — Arm spines opaque; disk covered with fine 



spines Ophiochceta, restr. 



Ophiolimna, emend., includes Ophiacantha hairdii Lyman (referred 

 to Ophiolimna by Verrill), Ophioconis antarctica Lyman, Ophia- 

 cantha perfida Koehler, Ophiolimna operculata Koehler, Ophioconis- 

 diastata and papillata of H. L. Clark and Ophiacantha lambda H. L. 

 Clark, and belongs to the Ophiacanthidse. Ophiuroconis includes 

 Ophioconis pulveridenta and miliaria of Lyman, besides the genotype, 

 Ophiuroconis monolepis sp. nov. Ophiurodon includes Ophioconis 

 cincta Brock, 0. grandisquaryia, permixta and cupida of Koehler. 

 Ophiurochceta includes Ophiochceta mixta Lyman (referred to Ophio- 

 limna by Verrill) and Ophiolimna littoralis Koehler. The last three 

 genera belong to the Ophiarachninae; especially Ophiurochceta is 

 very near Ophiarachna. Ophioconis, restr., includes Pectinura, 

 forbesii Heller (referred to Ophioconis by Llitken) and Ophioconis: 



