'38 MR. W. F. LANCHESTER OX THE SIPUNCULIDS [Jail. 17, 



Examination under the microscope of the skin of the introvert 

 shows that, for about half its lengtli, the papillse are similar to 

 those on the body, but that anteriorly they gradually become 

 flatter, the plates becoming much smaller and losing their con- 

 centric arrangement, so that the whole appears as a granular 

 area surrounding the centi'al opening. In the dorsal half of this 

 anterior region, moreover, they become surrounded by thick 

 bands of bi-own pigment which fonn a dense network between 

 them and tend to obscure their height, but in the ventral half 

 the pigment is absent aiid it is easy to trace their gradual 

 flattening (PI. II. fig. 1 c). 



This species is obviously very like Ph. psaron, but there are 

 certainly no spines on the introvei-t and the papillae difFei- in 

 certain features. Thus Sluiter says " Sonst kommen im Riissel 

 nur dunkle Leisten vor, aber keine gesonderte Papillen," which 

 hardly agrees with the arrangement found here. Otherwise the 

 geneial anatomy is closely similar, save only that the nephridia 

 a,re half and not three-quartei-s the length of the body, and 

 attached for two-thirds and not one-third of their own length. 

 Sluiter's description is rather brief and he has not figured his 

 species, but I feel reasonably ceitain that the two forms are 

 distinct. 



7. Phtscosoma gaudens, sp. nov. (Plate II. fig. 2.) 



Loc. Pulau Bidau, Penang. 



Three specimens. 



This form would appear to be the Eastern representative of the 

 Western Ph. %oeldonii Shipley. In all general features it closely 

 resembles the latter, but in regard to the papillfe of the body it is 

 distinctly difierent ; these consist, in Shipley's species, of a 

 number of brown horny plates with pigment in between, while in 

 the present species they consist of tv>'0 rings of small transparent 

 plates round the central opening, then a ring of about six large 

 brown plates, and then another more or less complete ring of 

 slightly smaller irregular brown plates, pigment granules being 

 absent (fig, 2). The actual resemblances between the two forms 

 are the relative shortness of the inti'overt and absence of hooks, 

 the brown papillfe especially crowded on the introvert, the 

 presence of only two reti'a,ctors, and the diverticula on the con- 

 tractile vessel. The difierences, except as regards the body- 

 papilla, are slight and obviously only difierences of degree, and I 

 give them in tabular form : — 



Ph. weldonii. Ph. gaudens. 



Longitudinal muscles 10-12, splitting- Muscles 14, splitting in the middle of 



into twQ in tlie middle of the bodj', and the body, but into more than two, so that 



fusing at hind end. posteriorly there are as many as 34 ; not 



fusing at hind end. 



Opening of nephridia a little behind Opening of nephridia at anus level, 

 anus. 



E«tractors arise at a level between the Retractors arise at the level of the 



aalevior two-thirds and tbc jwstcriov middle of the body, 

 one-third of the bodv. 



