PERCY SLADEN TEUST EXPEDITION. 



Description of the Species. 



1. Tubulanus polymorphus (Renier, 1804). (Plate 1. fig. 8; Plate 2. fig. 12.) 



Locality. Wasin, British East Africa (Crossland Coll.). 



A single small specimen lacking the hind end. The colour after preservation is pale 

 brown with a darker band 5 mm. wide, which begins about 3 mm. from the anterior 

 end. The external appearance is very similar to that figured by Burger for 

 T. polymorphus, and we are, on the whole, inclined to refer our specimen to this species 

 while recognising the following small points of difference. 



There are indications of a ventral muscle-cross in the ventral CESophageal region, 

 which are, however, not well marked and disappear behind the level of the excretory 

 pores. The diagonal muscles usually found in T. polymorphus between the longitudinal 

 and circular layers are not present, but this possibly is due to the small size of the 

 specimen. Again, the rhynchodaeal glands in this species are ventral, whilst in 

 T. polymorphus, as figured by Burger (Naples Monograph, pi. xii. fig. 9), they are dorsal 

 (PL 2. fig. 12). 



2. Prosadenophorus buergeri (Punnett). 



Literature. Punnett, R. C, Fauna & Geogr. Maid. & Lace. Arch. vol. i. pt. 1. 



Locality. Wasin, British East Africa (Crossland Coll.). 



A single specimen of this species was collected by Mr. Crossland. With the exception 

 that the proboscis contains 21 instead of 19 nerves, this form closely agrees with that 

 previously recorded from the Laccadives (Island of Minikoi). 



3. Drepanophorus roseus (Punnett). (Plate 1. figs. 4«, 4 ft.) 

 Literature. Punnett, R. C. Fauna & Geogr. Maid. & Lace. Arch. vol. i. pt. 1, p. 112. 



Locality. He Diamant, Peros Banhos, Chagos. From a colony of Mussa, 15 fathoms, 

 a single specimen measuring 40 mm. in length, 5 mm. in breadth. 



Dorsal surface dark red, ventral pale yellow. The head is characterised by yellow 

 markings (fig. 4 b). The small longitudinal head-furrows are conspicuous. 



In internal structure this specimen agrees very closely with D. roseus from the 

 Maldive Islands ; in fact, the only point of diflTerence is that the proboscis-nerves 

 number 23 in this specimen against 22 recorded for the type specimen. It is in all 

 probability a local colour-variety. 



There is a point of interest in connection with the excretory system, in that the 

 left duct passes round and over the outer side of the nerve-cord, while the right 

 duct opens to the exterior by passing along the inner side of the nerve-cord in 

 the usual way. 



The large blood-corpuscles which were such a feature of the type specimen are also 

 found here. 



