174 CEYLON PEARL OYSTER REPORT. 



scale in Herdman's species, against two large distal scales in C. verticiUata. The 

 outer lateral rows are somewhat reduced in Herdman's species, as they number only 

 5 scales, against 7 (or 6 if the most basal scale is considered as belonging to the 

 coenenchyma) in C. verticiUata. The abaxial rows in this last species consist of 

 9 scales each, all of nearly the same rounded form, and not extending over the sides 

 of the polyps, which are entirely covered by the scales of the well-developed outer 

 lateral rows. In Herdman's species the abaxial rows are formed by 10 or 11 scales 

 of rather diverse form, as 2 or 3 are somewhat prolonged laterally over the sides of 

 the polyps between the scales of the somewhat reduced outer lateral rows. The 

 upper margin of the polyp scales in Herdman's species is not strongly toothed, but 

 these teeth are well developed and more numerous in C verticiUata. In this last 

 species the operculum forms a higher and, consequently, more pointed cone on the top 

 of the polyp. The scales in the coenenchyma are of the same type, polygonal scales 

 with strongly toothed irregular borders, and with the outer surface covered with 

 radiating and anastomosing prominences. 



The species collected by Professor Herdman may also be easily distinguished from 

 all the previously described dichotomously branched species of Caligorgia, viz., 

 C. ventilabrum, modesta and compressa* It is more delicate, with smaller polyps, 

 and none of these three species has so few polyps in each whorl, even on its thinnest 

 twigs. 



There are, however, two new species in the collection made by the " Siboga " 

 Expedition in the Malay Archipelago, which in their habit, the dimensions of their 

 polyps, and the small number of polyps in each whorl very closely resemble 

 Herdman's species. They will be described in my paper on the Primnoidse of the 

 " Siboga " Expedition ; in this note I can only point out the more important differences 

 between these two species and Herdman's. 



One of them, C minuta, is easily distinguished by the much less numerous and 

 proportionately much larger scales in its polyps. The abaxial rows consist of only 

 5 scales, of which the 4 proximal ones extend over the sides of the polyps, where they 

 replace the outer lateral rows, of which only one large distal scale in the upper margin 

 of the polyps is left. 



The other new form, C. similis, is more closely allied to Herdman's species. But 

 while its polyps are arranged in whorls of 3, very rarely 2, on the thinnest twigs, on 

 the thicker branches the whorls number 4, perhaps even sometimes 5 polyps. On one 

 centimetre length of the twigs the same number of whorls (8) is found. But the 

 polyps are somewhat larger, measuring from 075 millim. to - 8 millim. in length, 

 sometimes even 1 millim., against 075 millim. or less in Herdman's species, and 

 consequently the distance of the successive whorls is on an average somewhat less. 

 The most important differences, however, are found in the polyps ; they are shown in 

 the following table : 



* C. elegans, Gray, is insufficiently described and a doubtful species. 



