lO 



form. That the very peculiar, arrangement of the spines on the cirri, which D.\r\vix called most 

 abnormal, occurs in Aurivillius' nova species also ("die eigentumliche Anordnung der Cirren- 

 borstchen des P. fiss2un findet sich bei dieser Art wieder"), is by all means a circumstance 

 strongly in favour of my view that they are really one and the same species. 



Aurivillius took still another species of Poecilasma from the same specimen oS. Palimirus^ 

 thrown on the shore of the Island "Noordwachter", one of the "Duizendeilanden" in the Java 

 Sea. He emphasizes that the main difference between this species and P. atnygdaliiiii is in the 

 structure of the cirri; these show according to him quite different characters, especially with regard 

 to the arrangement of the spines. In this second new species (P. lenticula) from Paliiuirus, 

 the cirri bear two long spines on the anterior face and also two short ones distally from the 

 middle of each segment; on the dorsal face, spines are only seen in the sutures. Aurivillius 

 gives a figure (1. c. Taf. VIII, fig. 28) to illustrate this detail of his P. Ie7iticula — but this 

 figure shows only spines in the sutures, on the anterior as well as on the dorsal side ! Some 

 confusion either in the figures or in the descriptions given by Aurivillius must have taken 

 place — but as he points out that the difference in the arrangement of the spines is the most 

 essential, one cannot help thinking that after all the reason for separating two forms of Poecilasma 

 as different species, which closely resemble one another in other regards and live together on 

 the carapace of the same specimen of Palinurus^ is not a very strong one. 



According to Darwin Poecilasma fisstctJi occurs at the Philippines; according to Weltner ^ 

 it has been collected by Fischer at New Caledonia, by Whitelegge at Port Jackson, by himself 

 at Jaluit (on Palitmrzis) and by Sch.\uinsl.and at Honolulu. 



The label accompanying the "Siboga" specimens only says that they were found on a 

 Palinurus at Ternate. 



5. Poecilasma excavahim n. sp. PI. I, fig. 5 — 10. 



Capitulum with seven valves, the scutum being divided into two segments by a fissure 

 nearly parallel to the occludent margin. Tergum with an excavation in the scutal margin near 

 the occludent margin to receive the tip of the occludent segment of the scutum. Carina narrow, 

 keeled near the inferior extremity, terminating in a disc. 



General appearance. Capitulum oval, less than twice as long as broad, with the 

 apex pointed, rather thick, swollen. Valves united without chitinous interspaces, peduncle cylin- 

 drical, narrow where it is attached to the capitulum (PI. I, fig. 5). 



Scutum. The larger segment strongly bowed, with a short basal margin and pointed 

 apex. There is a trace of an internal basal rim, but no tooth at the rostral angle is present. 

 Like the other valves the scutum is very delicately striated. The smaller segment is also 

 distinctly bowed, it terminates in a point at the base and has the tergal margin rounded so 

 as to fit exactly into the excavation of the tergum. 



Tergum triangular with a very characteristic excavation at the scutal margin near the 

 occludent margin (PI. I, fig. 6). 



• Weltner, \V., Ergebnisse einer Reise nach dem Pacific (Schalinsland 1896 — 97). Cirripedien. Zoologische Jahrliuchcr. 

 .•\bteil. ftir Systematik u. s. w. II, 1899, p. 441 — 447. 



