REPORT ON THE NUDIBRANCHIATA. 
3 
Family Phylliroida:. 
Psilosornata, Blainville, Manuel de MalacoL, 1825, p. 484. 
Phylliroidce, Bergh, Malacolog. Untersucli. (in Semper, Reisen im Arcliip. d. Pliilipp., Th. II. 
Bd. ii.), Heftv., 1873, pp. 210-246. 
Corpus magnopere compressum, altum ; postice nonnih.il humilius in caudam com- 
pressam apice truncatam, vel gradatim attenuatam abiens ; antice collo cum capite quasi 
boviformi conjunctum. Caput sat magnum, rhinophoriis contractilibus, pro parte vaginis 
retractilibus, simplicibus, elongatis instructum ; tentacula nulla. 
Bulbus pharyngeus fortis, illi Pleurophyllidiarum non dissimilis, ita quoque mandi- 
bulse fortes. Linguae radula non pauciseriata ; dens meclianus utrinque denticulatus ; 
dentes laterales non multi, utrinque denticulati. 
Glandulse hermaphrodisiacse discretse 3 ; glans penis conulis armata. 
These remarkable pelagic animals were placed among the Pteropocla by the earlier 
observers (Peron, Lesueur, Blainville) ; by other systematists (Lamarck, Cuvier, A. 
d’Orbigny, Cantraine, van der Hoeven, H. and A. Adams) they were incorporated with 
the Heteropoda ; they were transferred to the Salpse by Rang. Eydoux and Souleyet 
first clearly showed them to be “ nudibrancliiate ” Gasteropoda, though their affinity with 
the Gasteropoda had been previously hinted at by Eschscholtz. 
This Family contains two genera, Phylliroe and Acura, if indeed these be really 
distinct. Numerous memoirs have been published upon the former genus, but the 
structure of Acura was first made known through my Monograph. 
The Phylliroidse have a very remarkable form. The body is high and laterally 
very compressed ; at the posterior end it is lower and passes into a tail, which is either 
long and filiform (Acura), or similar iu shape to the body and truncated at its extremity 
(Phylliroe) ; the head, which is separated from the body by a more or less strongly 
pronounced “ neck,” is large and strong and somewhat high ; its shape is peculiar, 
owing to the presence (Phylliroe bucephala) of elongated simple rhinophoria, which 
can be retracted into their wide sheaths ; there is no trace of any tentacula. 
The bulbus pharyngeus is very strong and rather high, resembling closely the bulbus 
of the Pleurophyl 3 idiadse ; the mandibles are rather powerful, somewhat resembling those 
of the Pleurophyllidiadse, the cutting edge is densely covered with fine prominences like 
the teeth of a comb. The small “ tongue ” is entirely enclosed within the buccal 
cavity ; the radula is made up of an inconsiderable number of thin teeth. On either side 
of the median tooth, which is finely denticulated on both sides, are usually six lateral teeth, 
unsymmetrically denticulated on both sides. The liver consists of four long coeea, two 
superior and two inferior. The kidney is a long sac, opening internally into the pericardium 
through the renal syrinx, and externally by a short ureter on the middle of the body. 
The hermaphrodite gland consists of several — usually three — isolated lobes. The penis 
