igog.] N. Annandale : The Indian Cirripedia Pedunculata. 123 



edge of the distal half ; an imperfect separation into two joints sometimes visible. 

 Penis stout and short ; the proximal two-thirds covered with minute denticle-like 

 chitinous teeth and bearing scattered hairs, devoid of annulation ; the distal third 

 closely and distinctly ringed, bearing a comparatively small number of scattered 

 chitinous teeth, each with three comparatively long processes arising from a fiat basis; 

 the central process longer and more slender than those on either side ; a tuft of short 

 flattened hairs at the extreme apex of the organ, which is not retroverted, and a short 

 flagellum. 



Mouth parts. — Lahrum by no means bullate, bearing a tuft of short, fine hairs 

 at the distal extremity. Palp bluntly conical, bearing a terminal bunch of stout hairs. 

 Outer maxilla subquadrate, very broad ; the distal margin sinuous ; a fringe of stout 

 hairs running all round the edge, but shorter on the distal margin than on the dorsal 

 and ventral margins. Maxilla without an incisure, bearing a double row of stout 

 bristles, which decrease in size gradually from above downwards and are interspersed 

 with finer hairs ; the body of the maxilla bearing several transverse rows of rather 

 stout short hairs. Mandible with five teeth (including the inner angle, which is some- 

 times bifid) ; all the teeth rather short, not very widely separated from one another ; 

 the body of the mandible covered to a great extent with moderately slender, short 

 hairs. 



The capitulum of ovigerous individuals rarely measures more than 2 mm in 

 length. 



The external characters of this species are even more variable than is the case 

 in D. sinuata, the variation being of a similar nature but extending further in the 

 direction of reduction of the valves. The different forms that have been described 

 as distinct species and to which reference is made in the synonymy printed above the 

 description of the species, have been separated from one another mainly, but 

 not solely, on external characters, and it will, therefore, be well to preface a discussion 

 upon them by a brief statement as to the external differences which were believed to 

 separate them. 



(i) D. bullata, Aurivillius, had no carina or tergum; the scutum was somewhat 

 sinuous but not angulate; the aperture was obliquely vertical, short, broader below 

 than above; the capitulum was pointed above. 



(2) D. transversa, Annandale, had a small linear or narrowly triangular carina; 

 the tergum was absent or represented by a shapeless chitinous mass; the scutum 

 was sinuous or almost angulate ; the aperture was transverse or nearly so ; the capi- 

 tulum was produced above into a broad, rounded lobe. 



(3) D. angulata, Aurivillius, had a linear carina with a broadly triangular base; 

 there was no tergum; the scutum consisted of two branches meeting at an angle 

 greater than a right angle, the uppermost being the longer and broader of the two; 

 the aperture was almost vertical, narrow and slit-shaped; the capitulum was rounded 

 above with a small lobe. 



(4) D. aperta, iVurivillius, had a linear carina with a triangular base the lateral 

 angles of which were produced into distinct branches; there was no tergum; the 



