58 PROCTONOTID^E. 



they are hyaline-white, with a thin yellowish central gland 

 extending about halfway up, set rather irregularly on the 

 sides, about 3 abreast, those next the back large, the outer 

 ones small ; 4 large papillae are in front of the head : foo t 

 broad, slightly bilobed in front, without anterior angles, and 

 tapering to a point behind. L. 0-5. 



HABITAT : Dredged in shallow water in Malahide Bay, near 

 Dublin (Alder). 



Genus II. ANTI'OPA [*], Alder and Hancock. 

 [PI. II. f. 4.] 



BODY ovate- oblong, depressed : dorsal tentacles laminated, 

 and united together below by an arched crest : oral tentacles 

 short, with or without a slight veil : branchial processes ar- 

 ranged upon a pallial ridge along the sides of the back and 

 round the head in front: vent posterior, dorsal : mouth with large 

 corneous jaws and a denticulated tongue, containing numerous 

 smooth lateral spines and a single central one. 



This genus was named Janus by Yerany in 1844, and An- 

 tiopa by Alder and Hancock in 1848 ; but the name Janus, 

 having been previously occupied for a genus of insects, is in- 

 admissible according to the rules of nomenclature now gene- 

 rally followed, and which it is desirable should in all cases be 

 complied with, where it does not interfere with long- established 

 use. 



1. ANTIOPA CRISTA'TA, Delle Chiaje. 



Eolis cristata, Delle Chiaje, Desc. Stor. An. Nap. pi. 88. A. cristata, A. 

 & H. Brit. Nud. Moll. fam. 3, pi. 44. f. 1-7. 



BODY ovate, rather depressed, buffcoloured or whitish : dor- 

 sal tentacles conical, obliquely laminated, truncated at top, 

 yellow with white tips, united at the base for about a quarter 

 of their height by an arched crest, of a lobated pr radiated 

 structure : oral tentacles short, linear, set at the sides of the 

 head on a kind of conical hood : branchial processes very nu- 



[ * A mythological name.] 



