48 



LAND PLANARIANS PROM LORD HOWE ISLAND. 



In Mr. Whitelegge's collection are some specimens which are in all probability 

 young forms of the species. These are interesting as showing, what Professor 

 Moseley* has already drawn attention to, the curious fact that the markings are 

 often more definite in young than in old and full-grown examples. Two young speci- 

 mens are represented in figures 16, 17, 18, and 19. The first of these shows dorsally 

 three stripes of dark colour, (1) a median one and (2) two lateral ones. In the older 

 form these stripes, as it were, break up into a series of streaks and spots, but the 

 two lateral ones persist anteriorly, whilst the median one becomes more obscure and 

 represented by two lines of darker streaks. Ventrally also three dark but not so 

 prominent stripes are present each composed of closely placed spots. 



The second shows dorsally the lateral stripes strongly marked only anteriorly, 

 the median one being much fainter, whilst ventrally the lateral ones are only seen at 

 the anterior end, and the median one is much as in the adult. In both of the young 

 specimens figured only the pharyngeal opening is visible, the genital opening not 

 being apparently developed presumably on account of the immaturity of the 

 specimens. 



Rhynchodemus mediolineatus, sp. n. (PI. VI., Figs. 20, 21, 22, 23.) 



Dorsal surface with a median dark stripe which may or may not extend the 

 whole length of the body and on either side of which is a dark stripe anteriorly. The 

 lateral edges are marked by dark lines. Two eyes close to the anterior end. 

 Ventrally are two dark stripes one on either side the median line uniting anteriorly. 

 Pharyngeal opening 12 m.m. from the posterior end. Genital opening 6 m.m. from 

 the posterior end. 



Locahty.— Lord Howe Island. (Coll. Mr. T. Whitelegge.) 



This species varies somewhat in the development of the stripe just as does the 

 species Geoplana medioliiieata, which is distinguished by its median stripe. Two 

 specimens are figured. In the first of these (Figs. 20, 21) the three stripes are only 

 present at the anterior end dorsally whilst ventrally two extend for the whole length 

 and enclose the pharjngeal and genital openings uniting together at both ends. 

 In the second (Figs. 22, 23) the anterior dorsal end is darker than in the first and 

 the dorsal median stripe extends the whole length whilst ventrally the two stripes 

 are only present for not quite one-third of the length. The genital opening in the 

 latter was indistinguishable. 



Rhynchodemus diibius, sp. n. (PL VI., Figs. 24, 25.) 



Dorsal surface with ground colour of pale cream colour, anterior end with four 

 dark lines extending back not quite one-fourth of the length of the body the two 



* Trans. R. S. London. The Anatomy and Histology of the Land Planariaus of Ceylon. Vol. 164, 1874, p. 110. 



