TLYMOUTH NEMERTEANS. 431 



5. Prostomalongissimum(5;Yr/7.). (Burger. Monogr.Taf.III,Fig.l5.) 

 Locality : One specimen in a dredging from the Mewstone. 



The single individual which I describe under this name is identified 

 only with hesitation with the Neapolitan species. The description 

 Biirger gives in his Monograph agrees completely with the external 

 features of my specimen, and so does the figure cited. The most 

 striking characteristic is the transverse bar of bright red pigment 

 on the head. However, a great difference of habitat exists between 

 the Mediterranean and English forms, the latter living at a depth of 

 10 fathoms at least, the Naples specimens being very common on the 

 beach together with Emplectoiicma gracile. 



Geographical distribution : Naples. 



6. Prostoma robertianae {Mcintosh). (Mcintosh. Monogr. 

 PL III, Fig. 1, and p. 167, text Fig. 8.) 



Locality : Eame-Eddystone. 



Head separated from the body by a brown pigment ring, from which 

 a pair of longitudinal brown stripes proceed towards the tail. A 

 median white line is also present on the dorsum. Colour brownish 

 pink. The anterior pair of eyes is decidedly larger than the posterior 

 pair, which was not covered by the brown collar. Length 8 mm., 

 breadth \ mm. 



This rather characteristic Nemertean seems to live at a greater depth 

 than most of its relatives. Mcintosh describes it from the Hebrides 

 and the Shetland Islands at a depth of 6-8 fathoms ; Beaumont from 

 the Isle of Man at 15 fathoms, and from Valencinia Harbour at 1-2 

 fathoms; Bergendal from Kristineberg at 15-20 fathoms; while the 

 Plymouth specimen lived at a depth of 25-30 fathoms. 



7. Prostoma candidum {Mullcr). (Burger. Monogr. T. Ill, Figs. 

 13 and 19.) 



Locality : Asia Shoal and Queen's Grounds. 



A few specimens of this Nemertine were met with in dredgings from 

 Asia Shoal and Queen's Grounds. A characteristic brown pigment is 

 present at the cephalic grooves. The colour of my specimens was not 

 as green as in Burger's figure ; it agreed better with that of Mcintosh's 

 figure, in which, however, the cephalic grooves have not been repre- 

 sented. These cephalic grooves, the shape of the head and the bright 

 yellow colour distinguish P. candidum {Midi.) from the next species, 

 to which probably the majority of P. candidum. Riches, belongs. He 

 describes, however, a specimen from Eedding Point which seems to be 

 identical with Prostoma candidum {Midi). Length 12 mm., breadth 

 i mm. 



