608 EOLIDID.E. 



central, on the posterior half of the back. Genital orifice 

 at right side. 



The animals of this genus have corneous jaws. 



P. MucRoxiFERus, Alclcr and Hancock. 



Plate Z. Z., fig. 2. 



Ann. Nat. Hist. vol. xiii. p. 161, pi. 2 (as Vcnilia imwronifera) , and Ann. Nat. 

 Hist. vol. xiii. p. 407. — Monog. pt. ii. fam. 3, pi. 42. 



Body (half an inch long) ovate, broad and depressed, 

 caudally produced, yellowish-brown, with darker spots and 

 opake white specks on the back. Dorsal tentacles pur- 

 plish-brown, stout, wrinkled, and somewhat tuberculated. 

 Branchite inversely pyriform, colourless, tuberculated, ar- 

 ranged in twelve rows of three in each, the outermost ones 

 very small ; above the head are four branchia?. 



On a sponge in shallow water, Malahide, near Dublin 

 (Alder). 



ANTIOPA, Alder and Hancock. 



Body ovate-oblong, acuminated posteriorly. Head 

 covered by a small veil. Tentacles four, two dorsal and 

 two labial, the former lamellated and connected at their 

 bases by an arcuated crest. Branch ire ovate, ranged along 

 the prominent lateral margins of the back, and continuous 

 above the head. Vent central on the hinder portion of the 

 back. Genital orifice at right side. 



The crest between the dorsal tentacles markedly dis- 

 tinguishes this genus fFom Proctonotus. Like that group, 

 the animals of it have corneous jaws. A full account of the 

 anatomy of both these genera is included in the fifth part of 

 the " Monograph of the British Nudibranchiate Mollusca." 

 The genus is synonymous with Janus of Verany. 



