13 



he the creeping stem, wlieieou by closer investigation there will be discovered the small 

 transparent perpendicularly projecting cells. One seldom, however, succeeds in raising these 

 colonies entire; they are most frequently broken into several pieces by the dredging operation 

 itself, or in washing out the mud. 



('haracteristics of Genus and Species. 



We may, according to the preceding description, characterise the Genus Rhabdopleura 

 in the following manner. 



Gen. Rhalidopleura. Allman. 



Polyzoariuiu tubum formans tenuem, flexibilem, cylindricum, chitinosum hyaliinuu ex 

 stirpe compositum repente intus septis transversis in cameras plures discretas divisa quarum 

 utraque in cellulam cylindricam plus ininusve liberam et erectam stirpe vix angustiorem sub- 

 tiliter annulatam vel plicis acutis circularibus dense ornatam, oriticio simplice circular! termi- 

 natam exit. Stirps in tota longitudine chorda chitinosa, obscura, tenui, cylindrica, rigida, pulpa 

 vero niolli celhdosa impleta trajecta. 



Polypiilis nullo endocysto vel pallio parietibus cellularum connexi, sod modo fimiculo 

 roxtrartiU tenui et carnoso chordir, stirpis chitinossc aftixi, corpore forma elongato-ovata, cx- 

 treniitatc auteriore paulo ililatata et in ramos divisa duos cylindricos et attenuatos supra 

 vergentes et a se divergentes, quibus series duplex tentaculorum fiexuosorum affixa est. Se- 

 ries tentaculorum minime continua sed et supra et infra intervallo distincto interrupta, quarc 

 nulla adest corona tentaculorum vel lophophorus proprie dictu sed modo r/uo mmi tcntacuUfcri 

 raldr fle.rihilrs. Inter bases honim ramorum interne adest prominentia magna carnosa scuti- 

 formis ovalis vel subjjentagonalis pedicello brevi et crasso aftixa facie infcriore subplana ex- 

 tremitate antica libere prominentc attenuato-truncata, inferiorc corpori incumbentc medio 

 leviter emarginato superticic ubique dense ciliata. 



(h-ificiiim oris subventrale, transversum pone prominentiam scutiformom situm, ])Ostice 

 lobo rotundato ciliato limitatum. OUsophaijKS brevis et sjjatiosus constrictione distincta a 

 ventriculo sejunctus; ventriridus simplex subteres, posticc attenuatus et sine fine, ansani sub- 

 itam formans in intestinum transiens; iitfcstiimni antice porrectum tenue cylindricum lateri 

 dorsali ventriculi et a>sophagi incunibens, orificio anali circulari ad basin ramoram tentaculi-* 

 ferorum supine sito. Tractus intestinalis, vel corpus proprium polyi)idis, minime nudus, sed 

 cuticula distincta, tenui, hyalina circumcirca arete circumdatus. 



Musculi adsunt hhIU distincti, nequc retractores, neque protractores. Retractio Poly- 

 pidis solummodo funiculo contractili efiecta ; prutrasio singular! modo prominentia effici videtur 

 scutifonni prtvorali, at modum solesc gasteropodum. Et retractio et protrusio i)olypidis seg- 

 nissima. 



Spec. Rhabdoplenra mirabilis. (M. Sars). 

 Polyzoarium irregulariter tiexuosum sed raro modo et parce rainosum, stirpe cori)oril)us 



