id in m<>M regards this holds g 1 also for the male "I Ibla Cumingi, There 



is howe> tail which 1 found different from Darwin's description. Darwin speaks of an 



>n of the peduncle of the little male passing obliquely through the chitine 



ium lining the sack of the female, and running along amidst the underlying 



I inosculating fibrous tissue, attached to them by cement al the extremity. I have 



iys found the little male attached to the wall ol the sack b) means ol .1 di 1 ol cement, 



but 1 could n«u observe that it passed through thal wall. 1 think that the description given by 



Grüvel, where he ^.i\^ for ll>la quadrivalvis) thal the mantle Darwin's "sack") sometimes 



forms a proliferation, through the centre "I which passes the extremity "l the peduncle of the 



. explains what h.is been observed bj Darwin. According to Grüvei the tubular pan of 



the male "s'enfonce dans Ie manteau >1<: 1'hóte". This means, I think, that the mantle forms 



an invagination to receive the extremity of the tubular part, not that this passes through it to 



l with the muscles of the female's or hermaphrodite's pedun< [1 



This species w.is collected at the folio wing places: 



St.it. 51. April 19, [899. Shore-exploration in Madura Bay and other localities in thesouthern 

 part of Mi >lc > Strait. A few smal! specimens attached to Pollicipes mitella. 



St.it. 86. June 18—19, [899. Reef-exploration Dongala, Palos Bay, Celebes. Specimens loose, 

 i. e. not attached to Pollicipes mitella. (N.B. No specimens of Pollicipes were 

 collected at Station 



2. //'Ai sibogae n. sp. PI. IV. fig. 20—22. PI. V, fig. 1 — S. 



I emale. Valves of a uniform dirty brown or red brown colour — no blue, neither 

 along the lateral margins nor on the upper interior surface. Spines on the peduncle without 

 blueish brown rings. Caudal appendages only slightly longer than the pedicels of the sixth 

 cirrus; rami of the first cirrus unequal by 2 — 5 (as a rule 4) segments. 



Male. Closelv resemblingf that of /. Cumingi Darwin. 



This species is unisexual like /. Cumingi Darwin, which it also resembles in many other 

 Is. The absence of the blue colour, together with a few slight differences I perceived in 

 the structure of the parts <d the mouth, the cirri and caudal appendages, as also the circumstance 

 that /. Cumingi lives attached to Pollicipes mitella as a rule, made it necessarv to consider 

 the present form as a different species. Later investigation of a richer and il" possible quite fresh 

 or living material of both forms may show however that they are not specifically different but 

 only represent two varieties of one species. 



1 e m a 1 e 



The animals are somewhat variable in shape, that pari of the peduncle to which the 



capitulum is attached and which as a rule is considerably broader than the inferior part, sometimes 



forming an abrupt swelling and sometimes quite insensibly sloping into the inferior part. In other 



mens there is a distinct constriction beneath the broader part, almost in the middle of the 



- '. du "Talisman". Paris, 1902. 



