IO 



NEMERTINEA 



l.s 



Order I. Hoplonemertea. 



The proboscis is armed The epidermis rests on a thick layer 

 of connective tissue plentifully supplied with glands, below which 

 is a prominent basement membrane. 

 The muscular layers of the body are 

 two in number, an outer circular and 

 an inner longitudinal. The nerve- 

 trunks lie within the muscular layers 

 of the body and give off regularly- 

 arranged branches. There is no 

 nerve plexus. Each of the cephalic 

 slits generally opens by a pore situated 

 in the centre of a transverse groove, 

 which is beset along one side by a row 

 of shorter grooves at right angles to it. 

 FIG. 57. Anterior end of the The apparatus consists of a ciliated 

 :,S:!. C oUS";: ^t * m uM by nerve tin*, and 



tion of the prol >oscis ; /.*, lateral passing into lobes of tissue which ai'6 

 sacs containing stylets ; w.w, i , , , i i -i , i i 



muscular portion of the pro- connected with the brain by thick 



stylet ; s.t>, granular nerve-cords. 



basal portion of stylet. 



The mouth opens rather 



_ , . _ f , . 



far forward in front of the brain. 

 The intestinal pouches are symmetrically arranged. Auditory 

 organs are said to exist in some forms, consisting of vesicles 

 containing otoliths. The vascular trunks are connected an- 

 teriorly by closed vessels and not by lacunar spaces. 

 The principal British genera and species l are : 



Amphiponu Moculatus M'lnt, A. (lissimulans Riches, A. hastattis M'lnt., 

 A. lactiftoreus M'lnt, A. pnlcher Jolinst. 



DreiKinophorus rubrosti-idtns Hubr. ( = ^4. fpectalnlis Qtrf.). 



Tdrastemma ambiyuum Riches, T. cttiidiJum O. F. Miill., T. dorsale Abildg., 

 T.flavidum Ehrenb., T. immutnbile Riches, T. melanoccpJudum Johust., T. 

 iiigritm Riches, T. robcrtintiae M'lnt., T. ri-nnit'idutuin Qtrf. 



Protorhochmui doparedii Keferstein. 



Nemertea caroinophila Kiill., ^V. gracilia Johnst., A T . neeaii Oerst. 



Malacobddhi yraua O. F. Miill. 



1 Our knowledge of British species is mainly due to M'lntosh (JJritish Annelids, 

 Ray Society, 4to, 1873) and Riches (Journ. Mar. iol. Ass. vol. iii. 1893-1895, p. 1. 



