12 PERCr SLADEN TEUST EXPEDITION. 



Our specimen agrees with Joubin's species in possessing dorsal and ventral head- 

 grooves, a feature which separates it from D. formosa. As the material has only 

 reached us in the preserved state, we are unable to state whether the colour was pink 

 like that of a Joubin's specimen. In general anatomical features, such as the reduction 

 of the cutis, the musculature of the side folds, and the dorsal position of the excretory 

 pores, the present specimens agree with the descriptions by Burger and Joubin. 



20. Diplopleura sip. 



A smaU specimen belonging to this genus was found among certain material from 

 the Maldive and Laccadive expedition too late for inclusion in the report of that 

 expedition. 



[Appendix. — In the following Tables we have enumerated certain anatomical features 

 which experience has convinced us wiU prove of serAdce in the classification of the species 

 at present included in the genera Cerebratulus, lAneus, and Micrura, and we have 

 tabulated these features in so far as reference to the original descriptions has allowed us. 

 In cases where the records are too meagre for tabulation we have nevertheless mentioned 

 the name of the species. Most of the terms used do not require explanation, but we 

 ought to mention that in the case of the head-slits the term " not prolonged " means that 

 these slits do not extend beyond the hinder limit of the brain. A large black dot in the 

 right-hand column opposite a species signifies that the species so marked is found in tlie 

 Indian Ocean. — R. C. P.] 

 9th May, 1909. 



