1909 •] N. ANNANDAI.K : The Indian Cirripedia Pedunculata. 107 



Dichelaspis tridens (Aurivillius). 



Pœcilasma tridens, Aurivillius, '' Studien über Cirripeden/' Kongl.Sv. Vet. Akad. 

 Handl., xxvi, No. 7, p. 14, pi. i, fig. 13; pi vi, fig. 12; pi. viii, figs. 13, 29. 



Dichelaspis occlusa, Lanchester, ''Crustacea of the 'Skeat Expedition/ " Pj'oc. 

 Zool. Soc. Lond., 1902 (ii), p. 373, pi. xxxv, figs. 6— 6c. 



CapituIvUm laterally compressed, oval, produced into a more or less distinct 

 rounded projection in front of the tergum. Valves well developed, calcified, more 

 or less opaque. Carina broadly, regularly curved, expanded at the base into a well- 

 developed transverse disk, somewhat concave externally in this region, with a broad, 

 flat, inferior margin, which is co-terminous with the lateral surface above; a low 

 dorsal ridge generally running the whole length of the valve; the apex situated at 

 a point about half the distance between the carinal angle and the umbo of the 

 tergum, from the carinal margin of which the carina is often by no means widety 

 separated. Tergum irregularly triangular, with two distinct excavations on its 

 scutal margin ; its breadth more than twice its greatest height ; the umbo situated 

 on or near the margin of the capitulum ; the occludent margin irregularly curved, 

 diverging from the edge of the capitulum, with which it is in contact only at the 

 umbo. Scutum consisting of two segments, both approximating to the tergum above; 

 the occludent segment sickle-shaped, with the tip at the base and the upper extrem- 

 ity pointed or truncated^ extending considerably above the highest point of the 

 tergal margin of the carinal segment ; the carinal segment approximating closely to 

 the occludent, with which it is sometimes in contact above, sometimes almost 

 quadrangular, narrowly separated from the carina behind and almost in contact with 

 the tergum above, sometimes separated from the tergum and carina by a consider- 

 able extent of membrane and nearly triangular, the tergal margin sinuate, the 

 carinal almost straight. 



PEDUNCI.E as a rule short and stout, sometimes long and moderately slender, 

 ringed or smooth, covered with minute chitinous points, which often give it a deep 

 yellow colour. 



Cirri, etc. — First cirrus short and slender, the two branches subequal, each 

 with six joints. The three distal joints of each bearing at their distal extremity a 

 complete circle of long, stout bristles, the third joint from the base a similar but 

 incomplete circle ; a fringe of similar bristles on the distal half of the anterior edge 

 of the fifth and sixth joints and the distal quarter of the anterior edge of fourth 

 joint; the fringe on the posterior edge of both branches consisting of fine hairs. 

 The remaining cirri slender and rather short, very widely separated from the first pair, 

 each joint bearing, on its anterior edge, a double fringe of long, closely-set hairs, and 

 a bunch of rather stouter hairs at the tip of the joint behind. Anal appendages 

 somewhat variable in length, usually reaching the tip of the pedicel of the sixth cirrus, 

 bearing a pencil of long hairs at the tip and on the distal half or third of the posterior 

 edge. Penis long and tapering, minutely and regularly ringed, with a few short, 

 scattered hairs, chiefly on the dorsal surface, and a bunch of longer hairs at the tip. 



