101 



XVI. Fig. •"' "• Det omtalte, meuibranøse Overtræk er 

 slimet, svagt inkrusteret med Ler og har opad en skarpt 

 begrændset Rand, Tab. V. Fig Hb; Tab. XVI. Fig. id, 

 imedens det nedad ikke har nogen saadan Begrændsning, 

 men er forøvrigt saa tyndt. at naar Dyret er fuldt udstrakt, 

 tbrsvinder det næsten ganske tor Øiet. 



Physa er afrundet, blæreformigt opsvulmet og for 

 Størstedelen blottet for Overtræk; men ogsaa den har 8 

 tine Farer, der svare til Længdefurerne paa Sea] nis og 

 ligesom samle sig omkrin- en navleforinet Fordybning, som 

 ikke er perforeret, Tab. XVI. Fig. 4 e. Physa er vid kon- 

 traktil, forsåavidt den udvider og saniraentrækker sig. men 

 den kan ikke indtrækkes eller skjules af Skeden, og der 

 tindes paa dens Overrlade imellem Furerne lignende Suge- 

 vorter som paa Scapus, men de ere her meget sparsoin- 

 m ere. 



Capitulum er eylindrisk. 8"'"' langt, aldeles blottet fur 

 Overtræk, yderst gjennemsigtigt, glasklart og forsynet med 

 8 fine Længdefurer, Fortsættelse af de paa Scapus. og 

 imellem hvilke tindes ligesaa mange, lidt ophoiede Længde- 

 feltei, hvori sees spredte Sugevorter. Tab. V. Fig. 3; 

 Tali. XVI. Fig. 4/. Længdefurerne dele sig i to opimod 

 Oapitulums øverste, afrundede Rand, der bærer Tentak- 

 lerne. 



Mundskiven er hvælvet og har 8 tine Furer, imellem 

 hvilke tindes ophoiede Folder, der gaa fra Munden og 

 straale ud mod Skedens Peripheri, hvor Furerne dele sig 

 i to og korrespondere med de todelte Furer fra Capitulum, 

 Tab. XVI, Fig. 4. Mumien danner en Tverspalte og er 

 lidt fremspringende. Tentaklerne ere omtrent 8""" lange, 

 temmelig spidse og staa ved Grunden tæt i hinanden. De 

 danne en Række, Id i Antal. og ere meget retraktile. 



Farven. Scapus har et tint. gronligt. gjennemsigtigt 

 Overtræk. Huden indenfor er næsten glasklar, spillende 

 svagt i det Rode med blege, lyserøde Længdefurer. Naar 

 Dyret er fuldt udstrakt, har Capitulum et svagt rosenrødt 

 Skjær, hvilket ogsaa er Tilfældet med Physa. Mundskiven 

 er rosenrød med 8 blege Furer. Tentaklerne ere smukt 

 høirøde, Tab. V. Fig. 3. 



Dyret ligger los i det sandholdige Ler og ser ud- 

 strakt orinagtigt ud; men naar Tentaklerne ere iudtrukne. 

 og Legemet er udspændt af Vand. som Tilfældet var, da 

 det kom op af Skraben, er det omtrent '24'""' langt og 12""" 

 bredt og saa fuldstændigt glasklart, at de rode Tentakler 

 og Mesenterialtilamenterne kunde sees, og det lignede da 

 overordentlig meget en Myriotrochus brevis, som jeg ved 

 forste Oiekast ogsaa antog det for. 



Ved Tversnit viser det sig, at den inkrusterede Overhud 

 er dannet af en seig, slimagtig Masse, hvori er indleiret 

 fin Sand og Ler. uden at der kunde opdages nogen organiske 



ted tliey appear as a small white point in the middle of 

 a small oblong depression (Pl. XVI, fig. 5 a). The mem- 

 branous covering mentioned is mucous, slightly encrusted 

 with clay, and has at the top a sharply defined margin 

 (Pl. V. fig 3 6; Pl. XVI, fig. 4 d), whilst in the inferior part 

 it has no such margin, but, otherwise, is very thin, and 

 when the animal is fully extended almost entirely disap- 



pears to the eve. 



The physa is rounded, sac-formed, swollen, and for 

 thi' greater part is without anv covering; but it. also, 

 has 8 fine furrows, which correspond to the longitudinal 

 furrows on the scapus and. as it were, collect round 

 an imperforate navel-shaped depression (Pl. XVI, li^. 4 e). 

 The physa is indeed contractile, in as much that it ex- 

 pands and contracts itself, but it can not be retracted 

 or be concealed liv the sheath. and on its outer surface, 

 between the furrows, similar suckers to those of the scapus 

 are found. hut are. heiv. much more rare. 



The capitulum is cylindrical, 8""" in length. perfectly 

 devoid of covering. extremely transparent, clear as glass. 

 and is furnished with 8 tine longitudinal furrows. con- 

 tinuations of the furrows of the scapus, between which 

 occur the same number of slightly elevated longitudinal 

 areas, in which scattered suckers are observed (Pl. V, 

 fig. 3; Pl. XVI, fig. 4/). The longitudinal furrows divide 

 themselves info two up towards the eapitulunrs superior, 

 rounded margin, which carries the tentacles. 



The oral disc is arcuate and has 8 tine furrows, 

 between which elevated folds are found, issuing from the 

 mouth and radiating to the periphery of the disc, where 

 the furrows divide into two and correspond with the two 

 divided furrows of the capitulum (Pl. XVI, fig. 4). The 

 mouth forms a transversal fissure and is slightly protu- 

 berant. The tentacles are about 8""" in length, rather 

 pointed, and are. at the base. situated close to each other. 

 They form a series, 16 in number, and are very retractile. 



The colour. The scapus has a fine, greenish, trans- 

 parent covering. The integument inside is almost as clear 

 as glass, with a faint play of reddish colour, and has pale 

 light-red longitudinal furrows. When the animal is fully 

 extended, the capitulum has a faint rosy-red tinge, which 

 is also the case with the physa. The oral disc is rosy-red. 

 and has 8 pale furrows. The tentacles are a beautiful 

 bright-red colour (Pl. V. fig. 3). 



The animal lies loose in the sandy clay and. when 

 extended. appears vermiform; but when the tentacles are 

 retracted and the body dilated with water, as was the 

 caSe when the specimen came up in the dredge, it is 

 about 24'"'" in length and 12""" in breadth, and so per- 

 fectly transparent, like glass, that the red tentacles and the 

 mesenterial tilaments may be observed; it then appeared 

 extremely like a Myriotrochus brevis, which I, also, at the 

 first glance assumed it to be. 



In transversal sections it is seen, that the encrusted 

 outer covering is formed of a viscid, mucous mass, in 

 which fine sand and clay are embedded, but without any 



