174 CEYLON PEARL OYSTER REPORT. 



Muttuvaratu Paar, 45 to 50 fathoms, from the cavities of Coral. Eight females, 

 28, 27, 27, 25, 24, 24, 23 and 19 minims. ; eight males, 27, 25, 23, 21, 21, 21, 20 

 and 13 millims. 



Pearl Banks, Cheval Paar. One male, 24 millims. 



Talaivillu Paar. One male, 10 millims. 



Through the kindness of Professor Pfeffer I have been permitted to examine the 

 type of this species, with which I . find the Ceylon specimens in perfect agree- 

 ment. Lenz (1905) has recently pointed out that this species is a true Protosquilla, 

 combining, as it does, a tridentate rostrum with the complete fusion of the sixth 

 abdominal segment with the telson. It has thus no connection with Gonodactylus 

 spinosus, with which Bigelow, when describing the latter, compared it. A brief 

 description of the species is appended, and a figure of the endopodite of the first 

 abdominal appendage of the male given for comparison with that of other species 

 (fig. 19). 



The rostrum has the median spine very long and acute, extending to the corneal 

 part of the eye. The lateral spines are acute, but not as much produced as the 

 median one, and extend along the outer edge of the eye not quite as far as the 

 corneal part. 



The carapace is of about equal width throughout and oblong in shape. The 

 antero-lateral angles are acutely rounded, while the postero-lateral angles are more 

 broadly rounded. 



The lateral parts of the last three thoracic segments are rounded. 



The abdomen increases in width slightly from the front backwards. The postero- 

 lateral angles of the first three segments are rounded, while those of the fourth and 

 fifth segments are acutely produced. The first four segments have well-marked 

 marginal carinse, but are otherwise quite smooth. On the lateral parts of the fifth 

 segment there are two or three sharp carina? separated by slight furrows. The 

 central part is. almost smooth, except near the posterior margin, where a few short, 

 scattered, transverse furrows may be noticed. The sixth segment is fused completely 

 with the telson, though the suture is still distinctly visible. On its dorsal surface 

 there are four rounded tubercles, the median two of which are smaller than the 

 lateral ones, placed near to one another and separated from the lateral tubercles by 

 a furrow. The tubercles and lateral parts of the segment are thickly beset with 

 numerous, long, acute, upright spines. 



The telson is longer than broad, with its lateral edges slightly curved. The 

 posterior margin is cleft in the centre by a triangular fissure into two somewhat 

 diverging lappets. Each of the latter is again divided by a very much shorter slit 

 into two spines, which correspond with the submedian and lateral spines of the telson, 

 the intermediates being suppressed. The dorsal surface bears three very prominent 

 rounded tubercles, the median one placed anterior to the cleft, the lateral ones being 

 placed entirely posterior to the median, one on each apical lappet. The median 



