240 



face of each segment, and those situated at and near the upper extremity of the outer 

 surface of the segments not so dense as those on second cirrus. 



The fourth cirrus (PI. XX\ T , fig. 3) has 24 segments in the shorter (anterior) ramus 

 and perhaps a few more in the other this ramus being broken off in both cirri. Last 



segment of pedicel with a row of teeth along the front margin, which looks perfectly like a saw 

 in consequence. The teeth increase only very slightly in size from the base of the segment 

 towards the tip. A large number of segments of the anterior ramus show a series of such 

 teeth along the inner margin, the number of these teeth varying from 4 to 6 on the 1 2 lower 

 segments of this ramus. The teeth are somewhat claw-like and directed downwards, growing 

 somewhat smaller from the lower towards the upper segments. The i2 lh segment has only 4 

 of these teeth; the segments 13 to 15 have also 4, but they are directed upwards with their 

 tips. The segments 16 to 19 have 3, 2, 2 and 1 respectively of these teeth, which, moreover, 

 grow gradually smaller. The posterior ramus has no teeth on the 10 lower segments, and has 

 rows of 4 to 6 teeth along the inner face of the 9 following segments. These teeth are generally 

 somewhat smaller than those on the anterior ramus and are, as a rule, directed upwards. The 

 distal part of the inner face of each segment, in both rami, is furnished with a group of 

 spines which represent the pairs of spines seen on the segments of the other cirri : the lower 

 segments have only one pair, the following two to three pairs, placed so close together as to 

 touch each other at the basis. 



The cirrus of the fifth pair has elongate rami of 26 to 28 segments. Several segments 

 of the anterior ramus — in the specimen I investigated more carefully, segments 3 to 24 — 

 have the inner face or front margin furnished with a row of teeth, of the same shape but a 

 little smaller and less numerous than those along the segments of the 4 th cirrus. As a rule 

 each row has three such teeth, sometimes, however, four or even five. They are completely 

 r£\ wanting on the posterior ramus. They are as a rule curved downwards. The segments of the 



posterior ramus are furnished on their inner face with three pairs of spines. They are inserted 

 /.v,' along the upper half of the inner margin, yet not crowded together. On the outer face of 



each segment, close to its upper margin, a small group of delicate spines is situated : these 

 are longer on the lower than on the upper segments. 



The cirrus of the s i x t h pair has nearly equal rami of about 30 segments. The segments 

 grow — as in the other cirri — somewhat longer and more slender, from the basis to the 

 tip of the cirrus ; they become, even where they are most slender, not longer than three times 

 their breadth. 



Penis long, rather thick at the basis, growing very narrow towards the extremity. 

 Surface furnished with numerous short hairs which stand off perpendicularly from the surface. 



This interesting species is not represented in the collection of H. M. S. "Siboga". It 

 was sent to me with other Cirripedia taken in the Western part of the Malay Archipelago. 

 As it was studied by me along with other species of the same genus collected by the Siboga 

 in those waters, I think its description can be usefully inserted at this place. The exact locality 

 of its occurrence was : 



H. M. S. "Gier", N° 12, Experiment 13. Lat. 6°i5'S., Long. no°5o'E. Depth 40—50 m. 



112 



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