and Species of NucUbrancJiiate Mollusca. lo9 



Plocamopherus ncevatus, sp. nov. PI. VI. figs. 4, 4 a. 



P. elongato-ovatus, in regione branchial! promiuens, hac longitudinis 

 totius |- a capite sita, candidulus, irrcgulariter labeculis inequali- 

 bus fuscis maculatus, quae prope brancbias, post tentaClila dorsalia, 

 in margine pallii capitis atque ad latera eaudae confertse sunt ; 

 margine pallii capitis processibus brevibus tubereulatis instructo ; 

 tribus appendicibus couicis, sparse et minute tubereulatis, utrumque 

 ad dorsi latus positis, quarura posterior major est ; tentaculorum 

 dorsalium parte laminata conica retlectaque, intus fusca, extus 

 pallida, horum pediculis pellucidis, intra vaginas, quarum margo 

 minute crenulatus, retractUibus ; branchiis 5, anteriore centrali,, 

 reliquis utrumque ad latus ani positis, ex pediculo orieutibus, 

 ubique conferte maculatis, margine excepto ; ano tubulate ; tenta- 

 culis labialibus planis, ovatis, parce maculatis, margine crenulatis, 

 capiti conjunctis, parte extreraa laterali tantum libera ;' pede lineali, 

 antice lato rotundatoque ; eauda brevi, fastigio verticali, expanse, 

 fimbriato. 



The body is oblong, rounded in front, swollen and raised 

 towards the middle, and acuminated behind. The dorsal 

 surface gradually slopes from above the head up to the bran- 

 chial region, which is situated at rather more than two tliirds of 

 the total length from the head to the tail. The supracapital 

 veil has a short, free, upturned border, edged with short, sessile, 

 fuberculated processes. The dorsal surface bears three pairs 

 of lateral conical processes. The two anterior pairs are 

 minutely and rather sparingly tuberculated. The better-deve- 

 loped hindmost ones, situated at some distance behind the 

 branchiffi, have the bases swollen and with minute tubercles, 

 while the apices are large, rounded, smooth, and opaque. 

 The dorsal tentacles have the upper half conical, laminated, 

 kneed in front, and recumbent, pointing backwards and 

 inwards. The laminae are thirty-six to forty in number, and 

 half of them go completely round the tentacle. Tliey are 

 retractile through short sheaths, which have minutely crenu- 

 late edges. The branchias are five in number, short, thick, and 

 tripinnate ; they are placed one centrally in front of the tuber- 

 cular anus, and two at each side, arising from a short, broad, 

 lateral pedicle. The mouth is subterminal, opening rather 

 downwards. The oral tentacles are large, flat, ovoid or leaf- 

 shaped lobes, with subcrenulate edges, and are adherent to the 

 head except at the extreme lateral ends. The foot has in front 

 a shallow, semicircular, transverse groove; it soon narrows 

 and becomes linear for the greater part of its length, and 

 extends to the end of the tail. A longitudinal groove runs 

 down the centre, across which the wavy lateral edges can be 

 applied together. The tail is laterally compressed, and bears 



