an ee a ae Ne 
i a a al ll a el 
the Mouth in Sucking Crustacea. 19 
; | Aga. 
Os haustellatum. 
Haustellum adversum clypeo labroque, aversum malis poste- 
rioribus palpisque pedum maxillarium confectum, malas 
rendiiesens So, Pele priores rasorias involvens. 
Clypeus fornicatus pendulus. : 
Labrum semicirculatum, pendulum, fornicatum, margine 
7 membranaceo, fimbriate verruculoso. 
Mandibule stipite amplo, falcato, basi palpigero, mala inte- 
riore nulla. Mala exterior sub labrum oblique inflexa, 
mobilis, in orificium haustelli deorsum eminens, triquetra, 
acuminata, intra concaviuscula, apice extremo hamato, 
acuto. Palpus gracilis, triarticulatus, articulo intermedio 
_ producto, terminali brevi, falcato, barbato, pectinato, 
_ basin antenne secundee amplectente. 
axille priores stiliformes, mala interiore et palpo nullis. 
Mala exterior stipiti contigua, in orifictum haustelli deor- 
sum eminens, fasciculo armata terminali hamorum raso- 
riorum. 
Mazxille posteriores apice contigue, maxillas priores obvol- 
ventes, stipite lato, fornicato, palpo nullo. Male dis- 
crete, breves, rotundate, margine minute hamulate, ori- 
ficium haustelli post claudentes, supra marginem inte- 
riorem palporum pedum maxillarium reflexe. 
Pedes maxillares maxillas includentes, cardine maximo, obli- 
quo, laminato, triangulo, mala minutissima, conica. Sti- 
pites contigui, recti, subquadrati, fornicati, supra carinati, 
hypostoma valde elongatum medio carinatum utrinque 
explentes. Palpt quinquearticulati, latissimi, foliacei, 
fornicati, infra minute hamulati, labia lateralia haustelli 
formantes. 
Lingua rotundata, mollis, pulvinata, nuda, fissa lobis apice 
lingulatis, introrsum arcte contiguis, crasse marginatis, 
rimam suctoriam includentibus. 
13. Having now described the structure of the mouth in 
Afiga as minutely as seemed necessary in order to explain its 
composition and mode of action, we may, in respect of Cymo- 
thoa (fig. 6), content ourselves with a comparison between the 
two, pointing out and interpreting the differences. 
The oral tube is built up of the same elements; but they 
enter into its composition in different proportions ; and an im- 
portant difference in this respect is to be noticed between the 
two sexes. 
In the male the cardo of the mawillipeds is a large, trans- 
versely oval but very irregular plate. The stem is flat, ob- 
QF 
