(ind Species of Xwlibranchiate MoUusca. I'M) 



Plocnmopherus ncpvatus, ap. nov. 1*1. \'I. tigs. 4, 4 a. 



P. elongato-ovatiis, in rogiono branchitili proniiucns, hac longitudinis 

 totius » a capito sita, candidulus, irrcgulariter laln'culis incquali- 

 bus fuacLs maculatus, (jmc jiropt' braiichias, post tt'iitacula dorsalia, 

 in niarginc jmllii capitis at<iue ad latera cauda? conffrtic sunt ; 

 margin*' pallii capitis proccssibus brcvibus tubcrculatis instructo ; 

 tribus appendicibusconicis, sparse ct minute tubcrculatis, utrumquo 

 ad dorsi latus positis. (juarum posterior major est ; tentaculorum 

 dorsidiuin j)arte laminata coiiica rellectaque, intus fusca, extus 

 pallida, borum pediculis pellucidis, intra vaginas, (piarum margo 

 minute crenulatus, rctractilibus ; braucbiis o, anterioro central!, 

 reliquis utrumcjue ad latus ani positis, ex pediculo orientibus, 

 ubique conferto maculatis, margine excepto ; ano tulmlato ; teuta- 

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

 capiti conjunctis,])arte extreraa laterali tantum libera; pede lineali, 

 antioe lato rotundatoque ; Cauda 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 thirds of 

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

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

 tuberculated 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 

 branchia?, 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 lamina? are thirty-six to forty in number, and 

 half of them go completely round the tentacle. They are 

 retractile through short sheaths, which have minutely crenu- 

 late edges. The branchiaj 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 arc large, flat, ovoid or leaf- 

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

 head e.Kcept 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 



